I have done autos at 24/0 ,23/1 ,22/2 ,21/3 ,20/4 ,19/5 ,18/6 ,14/10 ,12/12....all the way to finish potting and DWC , finding 20/4 the healthiest looking plantgrowth set schedule .....also if you have started autos and photos going separately ,autos dont mind finishing a few weeks together under 12/12 as the photos are just starting to bloom well , the autos will finish sooner.....whatever schedule is started its ok to give them less daily light towards harvest that also helps better finishing temps....they like lower temp and more humidity than photos....I use RO water pumped through misters fanned at them spraying for 5-10secs every 30mins, changing to every hour towards finish ,then only 1 time a day spray setting just before lights on...and/or just spray by hand enough to keep them looking sweet.