I like to have 3-4 clones/ft² but mostly because I know how my ladies grow. I'd reccommend 1 plant/ft² on a flat scrog (it's a word now forks, the lettering no longer matters

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Scrog is great if you want to experiment a little as well since you get to isolate the buds and inspect closer. Veg time depends on your girls. Those that stretch the most will need less to fill the screen. Some will need a lot more. I grow a bit of this and a bit of that so I kinda fudge here and there.
Mostly you just have to experiment and figure out what works for you.
Mom plants don't have to be big, just healthy enough to grow clones when you need them.
Live, Learn, Grow.
BD