SCroG Advise!

Hello everyone, This is my first time growing indoors and i have decided to attempt the SCroG method.

I have a couple questions.
(1st) When should i stop vegging my plants and switch to 12/12?
(2nd) should i just weave them in and out of the SCroG to get the canopy effect?

Nothing? damn

Im doing my first scrog and im keeping the main stem under the net...............