Great set up, Got a 3m x 3m 4x4 type awning mounted on a 300mm high L bracket panel the same as you have, for our homebuild version if I ever finish it ..
With the big tarp fitted how does the L panel handle for flex in wind, didnt see any triangle braces . ... Edit . enlarged the pic, is that an Alluminium angle strip roughly 15o x 50 x 4 mm welded into a T shape .