I use 24/0, and I use pure flourescent lighting. I should probably use 18/6 since the price of electricity is so high around here lately, but meh, it's not like I'm running high wattages.

I'd guess 24/0 would help things grow a little faster, but maybe I'm wrong. I've never heard of it contributing to hermies and males, although I'd be interested to know where you've heard this. I've heard higher temps contribute to more males, so maybe it has something to do with the heat from the lights?