About now buddy if you are going to at all. Really you should have done in pre flower for autos and taken leafs that would have covered potential bud sites, giving the auto enough time to recover. Ppl say don't defol auto. But I've had great success with it. And haven't really done any heavy defol since wk 6-7. Best of luck. Have a look at my diaries I done defol to promote growth on a very sickly tangerine dream. It's good to light to bud sites, drop humidity and increase air flow. But once you have a constant air flow I wouldn't worry to much about air moving through them if that's why you want to defol but do it now, you'll need them leafs for energy for the mid to late flowering stage so don't take too much off one node. If you get away with leaf tucking and happy with light pen I wouldn't defol now just for air flow, just increase y9ur air if u that's why u wanna defol.
Happy growing buddy. Good luck.