that is your choice on when to do it -- i try and train the plants first a bit so by time it does reach a certain height then i will put up the netting
I know by pot size, how high I can hang my LED lights.
When plant is 2.5' from the groud. That's a foot or so for pot. 1.5" for the plant. In once in full Flower I'm right around 3.5'. Light needs to be 25"
this is in a 3.5 X 3.5 when it should have been a 5.5 X 5.5 -- lazy bud top on a Spider grow
i did late plant training as to help the look i was going for, this is set at about 13 inches from the main stalk split ( center stem ) just think of the possibilities if i had done early training and added a second net?. i could have set about 4 or 5 inches and been better off but it was not in original plan.
here is the last trim a day before harvest, most of the time i had the light set about 18 inches from the very top of buds,
hope this helps in ideas for your grow or at least a idea of how things might look