That is very close to what I am trying to achieve. You used heavier material than I, but very close in concept.I did something very similar for my setup. I integrated mine into the back of my stand instead of wall mounting with lengths that go to the floor so I can adjust up if needed. I used 45° sections for strength and it seems to easily do the job, granted mine is a single light on a 20G
I'm thinking about adding a horizontal piece and hard mounting my next light
I would have mounted to the stand but it became very busy with the uv mounting, overflows and header supports.
Thanks for sharing, I may change my material after seeing your design.