That piece in middle actually has a screw in each end and wheni twist it tight it doesnt move can remove it if i need to this way as well it was a last minute addition as i realized as i made the line tight it cause the outer pipes to bow in lollooks good to me .. I made my own out of pvc as well, but used 1/4 self tappers, but the same setup!! I would have put a tee in the middle though instead of the strings holding up the cross piece
3 inch by 3inchwhat size openings are those? Size matters when its a SCROG