‼️Advice wanted much appreciated‼️

First time growing in 20 years! All much appreciated advice and comments welcome! I just fimed ant topped my maybe two week old Seedsman cheese today. they were freebies.. none of the autos I ordered sprouted.. I’m actually waiting, their awesome customer service offered me replacements of their own brand. should I wait to start the megacrop nutrients I just got, or go for it and start feeding them at half the recommended dose or full dose? I also have the fox farms trio but I saw the megacrop on here and wanted to try it! Can I use both? Probably not right. I do appreciate some wisdom though! I’m gonna update and ask questions throughout my grow on this thread. anyone else wanna ask advice and share their grows are more than welcome! Share the knowledge! Hope everyone’s having a great day! Happy growing
So the question is should I star the megacrop today or wait? FF big bloom?
Half dose? Full dose?
How often do I feed them nutrients? Do I let them get close to dry before feeding? Sorry I know these are probably dumb questions! I see people on here doing multiple feedings a day in soil?!

quick info
Ones in 80% happy frog 20% perlite
Ones in 80% black gold organic and 20% perlite
Under a 1000 watt blurple with a supposed phenomenal par but all know it’s not true par. When I can afford some 3590 cobs/ vero timbers I’m definitely grabbing some.
tents 36x20x63

Ok here’s a pic after top n fim. I just got some good advice not to start the nutrients for a month or so bc of the soil they’re in, It’ll probably burn if not killer! I would’ve been pissed!