I tried alternating fire, but I prefer linked. Arondight has such a slow fire rate that I prefer to shoot all of them at or close to at the same time. That also helps with vent spamming.
For Dominator, I use two Mjolnirs and two Galatines. Four Galatines instead is usable.
Part of what makes Templars' ballistics so powerful is they raise flux on a hit. Secace Autocannon is mostly weak, but Galatine will tear stuff up. Arondight will incapacitate most ships whether you hit shields, armor, or hull. Their DPS is not that great, Galatine and Arondight is useful primarily for overloading ships.
Test the Ravana+Arondight against a capital ship. NO other weapons. You fire all 3 once, then the AI vents immediately. By the time you can fire a second time they are at 0% flux and you've accomplished nothing. Fire the same 3 shots on 3 second intervals and by the time you come around to the 4th shot they are still hovering at around 80% flux.
Then take that same ravina against a frigate. Fire all three at once, at least one WILL miss and there's a good chance all 3 do. If you hit the frigate dies, if you miss you are SOL. Put it on Alternating, you can fire one at a time, as soon as any one hits his shields are going to be at full overload for max duration. All it takes is a single hit to kill most frigates with shields down.
With the Dominator, the two guns are spaced so far apart you aren't going to hit anything but a Cruiser with both at once. Put on alternating and you can aim each one with enough precision to hit frigates. Use the second aim line to guide the first shot (while rotating the ship), which will always be a fixed distance away.
Maybe on something with turrets instead of hardpoints,,, I've been having trouble aiming those with my technique, so linked fire might work better. Of course, the Onslaught can't hit the same target with more than 2 at a time (and only if you aim off-center). Same for the Conquest, though that one is so finicky to aim I wouldn't bother myself.
Don't forget about the range difference either. The Arondight starts at 2500 and upgrades to over 4k. The Galatine only has a base range of 900, forcing you to fight close enough for the enemies to return-fire. It's like comparing an Anti-materiel rifle to an AK.