I've grown autos at 24/0 down to 12/12...under floros, up to 1000w hps....if they're GOOD autos, they WILL show sex by the 4th week of any light schedule....iow...they don't give a shit how much light they get, they gonna do their thing regardless....the amout of light and duration definitely does affect the yeild.....for one, I love autos...good potency and easy to grow.....
Right now, I veg 24/0 with T5...then move on to a 16/8 hps system....so easy to keep a harvest going on a specific schedule.....and if one throws in a girl that requires 12/12...it doesn't harm your auto at all.....only a bit of yeild, as the autos will finish on the clock!