I’ve never Scroged, but I’m familiar with the concept.
So, let’s say you want 1 meter colas, I would put my scrog at 1/1.2 meters. I guess you keep all growing tips at scrog level until flower then let them rip.
If you fill out a 4-50 foot screen your in business but yeah add more if you have to with that space you can still get to the hole screen and just manor it the Length of the fence
When I did it I actually just set it on the ground the screen unrolled it and had it laid completely out use 2x4s and you can adjust it if you need to put up a post put in at 16 inches and put one at 36 inches really just depends how tall you want it to get
I top my plants halfway between the medium and screen height. Then weave. I clean under the screen and yeah this creates better airflow. I would have the screens around 900mm high. Make sure you plant them far apart enough so that they don’t overlap too much.
I’ve been doing scrogs outdoors. 2 plants in a 5’x10’ Scrog.
I top twice, pull the plant to one side a bit, place the net about 1 meter above the deck, (I grow on a 3rd story deck), then bend and weave as she grows.
Last year I used some cheap trellis netting, it sucked.
This year I’m actually not growing Scrog. I was hit hard by bud rot and I think the dense canopy helped create the boytritis friendly environment. This year I’ll just top once or twice, do some lst, and let them grow normally.