I used to gradually increase the darkness by 1/hr a day, from 18/6 to 12/12 - didnt notice anything but more hands-on needed. Now I just flip it straight to 12/12, and call it "day 1"

Nutes, everyone has different opinions and needs, and it really depends on your soil or grow medium, feeding schedule, etc etc. I use Fox Farm Big Bloom myself and have had no problems, but theres many good nutes out there