I'd place this just below where you thick buds populate in the canopy. I err on side of below as to not hinder anything. Basically right when i flip the lights, that last ~18" of vertical growth will be up and through the screen and it'll support it, hopefully. You can always put more than 1 layer on. If they start flopping over, or first attempt was off a bit, no big deal.

Hey gardener! A trellis is enough, but if you want to use a net, you need to know when it stretches and by how much to keep a good distance between the light and the plants so you don't burn them. Good luck to you, bella ciao!

Elpiratahp, In my experience I’ve never had to scrog an auto. That being said, you have 150cm to work with. You need to take the measurements of the pot the plant is in and the appropriate distance from your light. What you are left with is the max height you can allow the your plants to grow optimally . If it is a photoperiod you would want to flip it at half that height to allow for stretch(possibly double in size) during flower.