I have recently started a "beam-only run" about three days ago, and I have been running a respectable midgame fleet composed of a bunch of Tri-Tach Brawlers, a couple Shrikes, two Furies, and a single Apogee, sitting at around 120 deployment points. As a true beam fleet, it's... alright. Here's how I've been outfitting them all (
haven't built-in any mods yet as I'm still figuring out a good fleet composition and this is definitely not a good fleet yet):
Spoiler
For the Brawler (TT)s:
1x Phase Lance, 1x Graviton Beam on the medium hardpoints, and 2x Tactical Lasers on the smalls. For hull mods, Flux Distributor, Extended Shields, and Advanced Optics. Max out caps and vents.
(As a note, this works for early game, but starts to drop off in larger fights since they rarely get chances to use their phase lance and extended shields are less useful when Salamanders get swatted by the PD of larger ships, which they'll be hanging around. I would recommend going double Graviton and replacing Flux Distributor and Extended Shields with Hardened Shields and ITU once you get into larger battles, essentially offloading their armor-cracking abilities onto bigger ships with HILs, but be careful making the switch as these ones can brawl with other frigates quite nicely while the dual-Gravitons struggle with them.)
For the Shrikes:
1x Phase Lance, 1x Gazer SRM Pod in the mediums, 2x Tactical Laser in the top-side smalls, 3x Burst PD Laser in the rest. For hull mods, Advanced Optics and ITU. I run 11 caps and 10 vents, but it doesn't matter that much.
For the Furies:
1x Phase Lance (top medium), 1x Graviton Beam (side medium), and 1x Gazer SRM Pod for the mediums. 1x Tactical Laser in the topmost small, and then 4x Burst PD Laser in the rest of the mounts (leaving that one that's immediately below the left small mount open). For hull mods, Advanced Optics and ITU. I maxed caps and then filled the rest of the OP remaining with vents.
For the Apogee:
1x High-Intensity Laser, 1x Graviton Beam, and 1x Tactical Laser in the hardpoints. 2x Heavy Burst Lasers in the back, and a Hydra MDEM Launcher and a Gazer DEM SRM in the missile mounts. Hull mods are Advanced Optics, ITU, and Stabilized Shields. I maxed out capacitors as far as I could go, but it doesn't feel like the best use of the remaining OP.
In combat, all I do is slap a Defend/Assault order down somewhere and wait. It takes forever, but an entirely soft-flux fleet can reliably win battles against equal-to-or-greater deployment point fleets (to a certain extent). What happens in battles is that my fleet balls up and fluxes out ships that approach the beam ball. These soft-fluxed-out ships then get a slap on the wrist from the beams (I have only one HIL in the fleet, so they often receive minimal damage), retreat, and get to try again multiple times until they get destroyed or retreat. Eventually... you win!
It does, however, struggle
immensely going against fleets with either very high armor or very high flux stats. A pair of Auroras in a Tri-Tachyon deserter bounty basically had to be completely surrounded by Brawlers to be destroyed. A single, undefended pirate midline orbital station wiped my fleet once. For "testing purposes" I went against a huge pirate blob I found at a fringe jump point, and while my fleet held off pretty well, I eventually lost due to swarms of Broadswords and Talons overwhelming my carrierless fleet and once I recovered, my fleet was out of CR and my Brawlers were gone. Remnants will probably be a nightmare for a beam fleet, and I am not going anywhere near them with my current fleet. Funnily enough, a beam fleet appears to be a great counter for phase ships, and any Dooms, Afflictors, or Gremlins you encounter will be fairly harmless.
For a better and stronger fleet, I'd ditch the Furies for Lion's Guard Eagles (they seem to be all-around upgrades since I'm not using the deep flux pool and fast speed of the Fury to my advantage here), throw in a couple Sunders with HILs (by my rules, I'd put mining lasers in the small ballistics slots of the normal Sunder, but Lion's Guard Sunders would be better since the small ballistics become hybrids for Tac Lasers), and put in a couple carriers like Drovers (since you can put four Gazers on them) with Sparks to take down enemy fighters. Adding a couple of Glimmers also looks to be well-worth the effort and skill points. In general, everything everyone has already suggested look to be great ideas, it just depends how aggressive you want to be.
The Shrikes and Brawler (TT)s look to be quite excellent for a beam-only fleet, and in particular, the Gazers really help with tipping the flux scales over to your advantage. The Apogee, not so much. It's still okay, but it can't deal any permanent damage by itself (it would be great with a Squall, but unfortunately that's not a beam) as it can't overflux targets, only damage already fluxed ones. Once I get a capital (any high-tech one or the Executor would be alright), it's going straight into storage. As previously mentioned, the Furies are not so great, as while they're really slippery and have great flux capacity, two medium energies mounting beams and a tac laser is almost nothing to anything its size and over. A normal Eagle with two Graviton Beams, an Ion Beam, some Tac Lasers and Burst PD Lasers, some Gazers, and a converted hangar with a Xyphos would probably be better at the same DP cost!
I haven't tested it yet, but Converted Hangars with Xyphos fighters sounds excellent to add in to a couple ships. Only four fighter wings have beam-only armament (those being Borers, Mining Pods, Sparks, and the aforementioned Xyphos), so we're limited in options. Depending on how strict you want to be with "beam heavy", Tempests look to be better than Brawler (TT)s, but unfortunately their Terminator drones have a single IR Pulse Laser.
For campaign advice, I found running immediately to Culann on game start to grab a contract that allows you to build from the blueprint catalog of Tri-Tachyon to be a good idea since it's kind of frustrating to grab, let's say, 10 Brawler (TT)s and 20 graviton beams from just flying around the place. Additionally, grab all the Gazers you can find, as they're weirdly cheap and you'll
really want them for later use.
Otherwise, that's all the advice I have so far, as I'm not so far into my playthrough. I apologize for the ultra-long post!