[heysoos99]

I use the same method. I bought (at Atlantis Hydro) the support brackets for building with 1 1/4" pvc pipe and made stands for my 3x3 E&F trays.
On the 1 1/4" pvc pipe cross members that support the tray-leave em long and mount an elbow on the four corners, put the elbow all the way up against bracket. . Mount vertical pvc in the elbows to height desired, mount add'l elbows at the top and tie together with pvc pipe on each side only, not across the ends. I don't glue the pvc but drill small pilot hole in fitting/pipe and use small sheet metal screws, easy to disassemble and move. I don't attach the very top cross-members elbows but just slide together. , allows me to bump off (small rubber mallet may be needed)top crossmember to work on lights etc with a little more room

Mount two levels of string trellis to the vertical pvc about a foot apart, the string can be very close to the lights and two levels adds strength to hold buds. I use plastic wire ties to mount. Plastic trellis is also available but the holes are smaller. I have seen highway crews using an orange plastic barrier that has holes and looks somewhat like trellis-I think this would work good and could problably be obtained for free.
Go to work training your plants, they are tough and can stretch horizontally all the way across the tray if you desire.
I also put mylar (mounted with short strips of duct tape) on the inside of the vertical pvc pipe. I only did the two sides, one side is against the mylar on wall, this leaves one side open for work and ventilation. Gets the mylar right up to the tray and this helps even with mylar on room walls.
I run 800 watts and fill the area completely across all the way to the mylar on sides and tray edges front and back.
Great post, thanks.