Run the plant in 18/6 all the way through at a minimum. If you try to run it in 12/12 it can diminish your harvest. Don't try to clone the plants either.
I like 19/5 for a light cycle the whole time VEG and Flowering anymore you may stress the plants and bad things can happen.. Heres my sexy bitches. auto widow, auto blueberry, lowrider #2 "5 weeks from seed !" some big autos
Good luck, and have fun.
Hell yea thats very nicely done, i went with flash auto's its just sprouting today, about to drop the lights on it, surely going to go with the 19/5 lighting schedule.
Not knowing what medium your using I'd say about 5 days to a week and then maybe a half shot of nutes till they start going good, I use rockwool myself and I use a little vitamin B plant starter from day 1.. but I'm no expert at it myself, I have a hard time trying to not over water them when there small ..
Also PeteSwitch 18/6 is good to he maybe better to ask about when to start the nutes..