I would feed according to the schedule. Watch your trichs for the coloration you want.when you see that you will want to harvest in a couple more weeks, start your flush.
Yes you can. Use it as you would for any other regular or fem. The thing wiht “autos”…They do not finish in under 100 days for me. I think I am averaging 110 days from sprout to finish, using an 18/6 photo period. If you want an “Auto” to finish sooner, shorten the photo period. 16/8, or 14/10 (excellent), or 12/12.