i personally look at the tirchomes to go 30% amber 70% cloudly before harvesting
i normally trim a few upper leaves to allow light to get through to the bottom
if your struggling for cash go on a seedbank and just order the cheapest
unless someone on here or that you know has some seeds you wont get any freebies
well im thinking that your seedlings will probaley stretch if you put them in now unless you got a good tall table,
regarding switching back i aint sure
my suggestion would be leave lights on 12/12 and just put your seedling on the window ledge out of neighbours site like upstairs
ive been using vitalink which a good cheap alternative but im going over to greenhouse seeds feeding powder cause thats only 25 for 500gram of powder and you use it throughout the plants life instead of switching from growth to bloom saving you cash by doing so