Bigger the tank the better, give them room to spread out. I have 55 different percula family clown fish (darwins, helmets, picasso grade A & B, and platiums) each species of them came from the same clutch from local breeder; in a 180g tank with 24 BTA's. They are spread out across tank.. more the bta the marrier!!
Mine are spread out evenly across tank, aggression is way down (if any). Also, all of them shot straight into the BTA from the net when I introduced them to the tank. Check out my thread in this forum:
http://www.reefcentral.com/forums/sh....php?t=2651161