How many 580 EXIIs at full power are needed to produce the same effect as one Alien Bee B800 at full power? I can't seem to find a numerical comparison between the two flashes. I asked that because soon I'll buy an Alien Bee and don't know which model to choose. B1600 may be the most powerful, but even at 1/32 can still cause overexposure (theoretically) and the opposite for the B400.