Auto's should be grown with 20/4 or 24/0 light indoor. They grow small enough its like thats what they were designed to do. If you were to use them outdoors, I would think its to get 3 crops out of the growing season, but your yield per plant will be less because there will be less light than you can afford them indoors.
Seriously, Autos = Indoor only. I'm using them to get a crop out of a dormant flowering room while my mother grows and clones veg. I'll do a log of my Diesel Ryder once I get construction of the room finished.