Welp, since the tournament is over I decided to write out an overview of my midline fleet in case anyone was interested in some of the considerations I had designing my variants and thoughts on the viability of other midline ships under this ruleset. Plus it's good to have it out in writing, anyhow.
Imgur album of final variantsGryphonSpoiler
Basically as soon as the officer rules were proposed (i.e. I could have the Missile Specialization skill) I decided that I wanted to run Gryphons. I have a soft spot for them since lots of people think they are absolutely terrible AI ships and I, uh, don't. They're fantastic second line ships and since they don't have very high weapon flux they're respectable on the front line as well.
Weapon Groups and Choices
The core to making a usable AI Gryphon is linking the large and medium missiles, since otherwise they'll be prone to firing one but not the other (except maybe Harpoons? But then you can't have Sabots :V). I chose a mix of Locust+Sabot since they're universally good (even despite the tournament nerf for the Sabot), which is important given the autofire nature of the Locust, and have similar refire times. Originally, I used Annihilators in the small missile slots to get maximal longevity (since they last nearly as long as the Locust), but after feedback from DaddyPants, I swapped them to Reapers which did well but didn't fire as often as preferred, leading to the ultimate choice of Harpoons. For the medium ballistic I also considered the Heavy Needles, the Hypervelocity Driver, and the Dual Flak Cannon. The former was expensive in credits and OP and easily shield flickered (bad with the emp-less Sabots), the HVD had the first two issues and low DPS (but would probably still be generally acceptable), and the DFC severely messed up the rangefinding of the ship, so that despite being PD the ship was in even more danger than the Heavy Autocannon. To save on OP I dropped the back left Vulcan, assuming that the two Vulcans on the front right would provide adequate cover.
Other stuff
Finally, I opted for a 30:1 capacity to dissipation ratio - around 15 seconds to vent from max flux, which is generally enough to fully reset between waves. Hullmods are kinda self-explanatory: ECCM for missiles and Efficiency Overhaul saves 4k in maintenance for relatively little cost. Unofficered Gryphons were set to Aggressive (default for every ship in my fleet was Reckless) to limit the chance of them dying horribly due to variance.
ValkyrieSpoiler
I didn't really think about using Valkyries when planning out my fleet, till someone in the tournament chat pointed out just how absurdly cheap the Valk is. 20k upfront is equivalent to a Centurion, but at 3 DP it ends up being even cheaper to maintain.
Loadout
I initially threw on some Converted Hangar Partisans from SWP, which are fairly strong interceptors with 2x Swarmers, but it became clear the battlespace was too large for them to be especially useful, so I transitioned to Thunders where possible. In the first round, there were no Sensor Relays to provide ECM Rating, so during refits I also added ECM Package, though this became unnecessary by the final rounds. Finally, although it's generally terrible value, I put EO to save 600 credits when required (e.g. round 2). One to two tac lasers were used for range finding, but I didn't think about it too hard.
DroverSpoiler
No midline fleet would be complete without them. I went through over half a dozen Drover variants and I'm still not sure what the optimal variant would be.
Weapons and Fighters
For round 1 I heavily prioritized the use of Khopeshes for the heavy HE that wouldn't miss as much against the slow low tech ships (the tournament nerfed Reserve Deployment for fighters--no extra wings--but basically left bombers unaffected). In later rounds, I began transitioning to Thunders both due to increasing ship speeds and the battlespace becoming too large for other fighters to cross the distance effectively (they weren't the obvious choice due to the aforementioned RD nerf, plus another nerf making the Ion Cannon high delay). The four missile mounts used Harpoons, though I also considered the use of a single linked auto-firing weapon like the Hornet or Salamander (it didn't test well firing all the Harpoons asap). I used Vulcans when permissible by OP and Reliants otherwise, though the latter are so bad it'd have been worth considering just leaving the slots empty.
Other Stuff
The main considerations for hullmods were Expanded Deck Crew (mandatory), Efficiency Overhaul (saving 2.4k credits per round--also mandatory), Hardened Subsystems (reasonable since in testing they sometimes suffered from CR death), and, when DaddyPants suggested it, Expanded Missile Racks (adding a total of 32 Harpoons by Wave 6 for 12 OP is in hindsight an extremely obvious choice). After the possibility of multi-directional waves became apparent I changed the personality of the ships from Reckless to Cautious. This ended up causing problems for the Thunder Drovers, since they would end up escorting ships instead of aggressively attacking; I dealt with this by introducing a mixed Khopesh and Thunder variant. The Drover provided a lot of room for variation, and there’s probably still room for refinement.
HammerheadSpoiler
Despite generally being the shining star of Midline alongside the Drover, I wasn't too enthused about using the Hammerhead, even before the rebalance to their rear turrets (better angle behind, can't point forwards). They were simply too expensive maintenance-wise to prioritize in the early rounds, and they were edged out by Brawlers (at least, pre-changed Brawlers) in the later rounds.
Loadout
In any case, I simply used a Safety Overrides variant prioritizing flux capacity. People also still question the inclusion of Extreme Modifications, so here's my explanation: Automated Repair Unit reduces the penalties of using EM but costs only half the total OP, so in exchange for occasional mitigated malfunctions I get the bonuses of ARU plus an additional 6 OP. The value of ARU is especially significant between the 20-40% Combat Readiness range, since the natural malfunctions will also be repaired faster. This means that while other ships have a massive decrease in performance once they reach the 40% CR threshold, EM-ARU ships only slowly decline until they hit 20% CR, effectively flattening their performance curve (note that they have significantly more problems below 20% CR, but the fleet was designed to rarely reach that point). That's an extra 80 seconds of adequate performance relative to other ships, and since for my ships the extra OP was shuffled into Hardened Subsystems, there's a further 20.67 seconds gained per round (on top of the usual benefits). EM-ARU is a damn good combination that almost all non-carrier ships should at least consider. Also the Railgun nerf (to 8 OP) hurts the non-SO version of the ship.
CenturionSpoiler
One of the most underrated ships in the game (except to Thaago!), the Centurion has a fairly high upfront cost for a frigate but pays for itself many times over given how tanky they are. Damper Field is an incredibly powerful system, possibly the most powerful after RD and the Astral's Recall.
Early Loadout
They're further boosted by the ability to use SWP's Contender Cannons, which are a low OP, low Flux HE small ballistic that isn't abjectly terrible like the Light Mortar. Since Railguns were nerfed and Light Needlers were buffed (to 7 OP), I used the latter as my kinetic option. Armored Weapon Mounts provided more per-OP value than Heavy Armor, and Hardened Shields are basically always good value for frigates with over 3600 capacity. Shield Conversion - Front gave the ship full coverage and reduced the relatively high upkeep. The aforementioned EM-ARU-Hardened Subsystems help to maintain longevity. The only issue with the latter combination is that Extreme Modifications and Efficiency Overhaul are incompatible, so when using the latter hullmod to deal with budget gaps (800 saved per Centurion) there would be a minor dip in performance.
Late Loadout
By Round 4, the lack of good point defense in my fleet was starting to feel problematic, so I swapped to a variant that switched the two Light Needlers for a Railgun, a Vulcan Cannon and IPDAI. Unfortunately, I had to drop Armored Weapon Mounts to fit them in.
BrawlerSpoiler
The Brawler is another amazing, top-tier frigate, but has a very low upfront to maintenance cost ratio, so it couldn't be effectively implemented until the later rounds. The tournament also uses the next version of the Brawler, swaps Damper Field for Maneuvering Jets, but adds 60 degrees of shield arc as well as increased capacity and dissipation. Honestly, the loss of Damper Field makes it a major nerf and kinda kills the viability of close range variants.
R3 Loadout
Opting for a more stand-off oriented build, I debated between double Heavy Autocannon and HAC and a Heavy Mortar. HVD and Heavy Mauler would be too expensive and wouldn't help with the ships' frontline role anyways. My initial builds used Harpoons in the universal slots, but eventually I opted for Reapers to save OP. Since I no longer had Damper Field to vent flux, I opted for a capacity heavy build. Additionally, although the minimal number of engines means that Extreme Mods can cause them to flame out or otherwise spin erratically (see DaddyPant's Nanzhongs for examples), the introduction of Maneuvering Jets meant that there would generally be enough maneuverability to make it workable.
R4 Loadout
In general whenever I wanted to save on credits, I preferred to use Efficiency Overhaul on my Brawlers over my centurions, both to reduce the spins due to flameout and because the Extreme Modifications Centurion variants significantly outperformed the EO variants. I used two different variants: one standoff going for HAC and Heavy Mortar (instead of dual HAC) with EO and one CQC with an HMG and a Flamer with Extreme Modifications.
Comments on other midline ships:
Spoiler
Conquest
Despite its questionable AI performance, I really wanted to make the Conquest work. It had a lot of potential as an officered ship for relatively low cost and maintenance. Unfortunately due to hiccups with the test mission I didn't have the chance to adequately test them. Next time I'll bring one with ACGs.
Victory (SWP)
Let's see, it's exorbitantly expensive compared to the Conquest, has terrible maneuverability, worse missile slots and only works in one direction. I had severe doubts about the Victory's effectiveness and never seriously considered one. (That didn't stop me from trying a Shield Bypass one, but it was predictably terrible.)
Heron
Between the Valkyrie and the Drover, I didn't really have a need for yet more carriers. Plus cruisers are expensive and I already had 2 Gryphons in my Round 1 roster (the only time the addition of a Heron would make sense). Absolutely not a bad ship though.
Owl (TADA), Vulture (SWP)
Both are interesting SO-ships. The Owl's 135-degree front shield arc makes it kind of unusable, and once again cruisers are expensive, especially since EM-ARU-HS means I can't run Efficiency Overhaul.
Eagle, Falcon
The former is an all-around decent ship, but the standoff variant with HVDs and Heavy Maulers wouldn’t fare very well working with my extremely wide Tiandong partner, and an SO build suffers from similar issues as the Vulture - there’s just too much opportunity cost. Regarding the Falcon, since wave combat with restoring CR heavily emphasizes DPS (part of why we went Safety Overrides on so many ships), I didn’t seriously consider the Falcon which has lower offensive potential than even a Hammerhead.
Albatross (SWP)
Honestly I really like the Albatross. It has superb PPT and excellent maintenance stats coupled with a strong hull and decent flux stats, and of course the incredible Damper Field ship system. The only reason I didn’t end up using them was that the midline destroyer niche was already filled by Drovers and Hammerheads, so there wasn’t really an opportunity to put them to good use. In my opinion, they’re one small OP buff away from being an integral part of midline fleets, which is imo a good position to be in.
Archer (SWP)
DaddyPants argued Archers were worth using, and they certainly have decent viability with 3 medium missile mounts at a decent budget, but I couldn’t design any fits for them that seemed especially good. They were also annoyingly fragile.
Sunder
As I mentioned with the Albatross the destroyer budget range was unfortunately already saturated, so the Sunder didn’t really get a chance to be considered. In general, they were even more fragile than the Hammerheads while having lower PPT and higher maintenance costs.
Vigilance
Cheaper upfront than a Brawler at 10k, but the high maintenance (also 10k) relegates it to being a round 4 purchase at most. DaddyPants seemed to like them, but to me it felt like they were made of paper and died to nearly anything.
Pest (TADA)
At 8k, it's an interesting option, but any time I had 5+ EM Centurions/Brawlers I could just swap them to EO and grab another Brawler instead.
Monitor
Terribly expensive at 25k credits per hull, along with high maintenance (12k per round) for a frigate and basically abysmal DPS made the Monitor just obviously non-viable.
Thanks Tartiflette, Nia, the casters and the participants for making this tournament as entertaining as it was! Thanks also to DaddyPants for being a very competent partner who let me steal his budget.