Autos will certainly learn ya something...mostly to leave'm the fuk alone. I've grown autos/photos for 15 years and ruined a lot of'em by trying to push the rope. Back then autos were mostly short and stocky and were developed to hide among other plants...as they became popular, breeders added more photo genetics to broaden their lines and autos are now mostly large plants with some photo characteristics. I don't give a shit cause I grow everything under 12/12 anyway. I likem a lot and they actually garner 70% of my grow slots.
Regardless, I'm still growing them alongside photos...I've had autos finish UNDER the breeders stated time but most do go over a bit and a few a lot more. Stick with known auto breeders and your fire will be assured.