Thought I\'d log in to add my thoughts here [even if this is bordering on thread necro].
IMO, a single antimatter cannon [I think these should be emphasized to not be lasers, since lasers aren\'t projectiles, etc.] should have a relatively high fire rate, low damage, and fairly slow velocity. As you add more cannons to a chain, the damage [per cannon] should increase, it should fire more slowly, and at much higher velocity [as happens in real life]. Think a handgun compared to a battleship cannon.
Right now it seems like the best tactic is a large number of single cannons, and just saturate the area with fire. Large cannons are fun, but not nearly as effective [except against single large vessels].