Whats a good weapon setup on a carrier?
Depends on what you are trying to do, and what class your captain is, as well as what skills your bridge officers have.
Plasma is always a good choice cause of the plasma fire (that applies with Eject Warp Plasma, Plasma Beams or Plasma Torpedoes, but it doesn't stack). Anti-Protons too are a good choice, as they deal 20% more crit damage.
The others are alright too.
Polarons have a chance of damaging all subsystems of the enemy, while Phasers have a low chance of entirely disabling a random subsystem for a few seconds. If you have a science officer, either of those 2 are a good choice.
Tetryons deal extra damage to shields (very useful AGAINST a science officer, lol).
Disruptors are able to do a defensive debuff on the enemy.
Regarding torpedoes, I would say the best options are either between Hargh Peng, Plasma and Quantums. Take Plasma torps if you don't have any plasma beams or don't want to take them. Quantums deal a lot of damage with one shot, which can be invaluable for slow craft like carriers or cruisers, and Hargh Pengs deal radiation DoT and AoE when their secondary explosion goes off. Both Quantums and HPs however have long recharge times.
That's all IMO, though. I love using Anti-Protons/Polarons (AP dual cannons, Polaron arrays) and one torpedo launcher on each side of my BoP (Plasma on front, HP in aft). Since the carrier is slow as shit, dual cannons are not a good choice (unless you wanna take out one of your torpedo launchers), so arrays, single cannons and turrets are definitely a better choice.