I like plain white mason line with 4" spacing and knots tied where the lines intersect. Usually train the plants for 1 cola per square. Manifold the plants so you can get one good solid top for sure instead of trying to fill the net with tops from small sicker branches.
I like to use screws so I can double wrap on the ends to keep tension.
Wooden dowels inside the pvc helps with rigidity and adds a little weight for stability.