I have always ran them on 24-0. Some people say 18-6. The dark, as we know, is when the magic happens-THC production, the enzymes are firing off everywhere, resin gets produced heavily, etc etc..
@TorturedSoul sent a few links off to
@ELLISJ I'm sure he will send them to you now that he is tagged in here Or you can go to E's post and look up all the responses.
@013 Had good info also. Apparently though there was a study done with 3 sets of autos on 3 different light schedules and the yield on the 20-4 was the best. But as you know, every strain is different, all the light set ups are different and yield is one thing, quality another. To each his own, I am thinking it doesn't hurt to try them on a different schedule this time, see what happens...makes sense, they like to rest even if they're autos and the ratio of flowering/total grow time to hours of light/dark compared to that of a pheno seems pretty appropriate....totally up to you but like I said there is a lot of information on lighting and light schedules out there for you to troll