I've got a Wells class that specializes in exotic damage only. I've been toying with the idea of using all harpengs since I'm not buffing any tac abilities at all.
My damage is done mostly thru gravity well 3, eject warp plasma, theta radiation, isometric charge and that new lock box console. Currently I use fleet plasma torps with the Romulan hyper, omega and Breen transphasic
New Rule: Please refrain from naming your starships after reproductive acts, or bodyparts. Nothing says I'm still a virgin more.
if you have 3 purple projectile doffs then everything except tricobalts hit global cd on firing (1 second), so quantum would do more damage if you are not using spire set. And for pvp transphasics are the torp of choice (mainly because of breen cluster torp)
I'd suggest chroniton or plasma.
Photon is a fast loader which makes it possible to do 2 shots in one ambush.
Quantum is good for a fast cloak-recloak hit, because it hits big.
Chroniton is good to make the enemy an easier target for other teammates. If multiple chroniton effects stack it makes an enemy move like a slow slideshow.
Plasma is good because of its shield ignoring DoT and the heavy torp's damage.
Photon and quantum does not have a secondary effect.
Chroniton's DPS and damage/shot is quite weak compared to photon and quantum torps.
Heavy plasma torp can be shot down and can hit you when you are close enough to the explosion.