I finally had time to build the rest of the light modules and cut + assemble the enclosures. I need a total of 7 for my install + 1 for testing. The captive nuts work well for assembly, but unlike my first test one none of these were able to friction fit so I had to hold each nut while trying to get the screw into it.
I think for the retail version of these I will get rid of the captive nut and will instead just use 4 long screws through the top and into the bottom layer on small wings to the sides. It will increase the footprint of the modules a bit, but it will lower my BOM (4 screws instead of 8 screws 8 nuts), and it will make it so much easier to assemble these.
Next step is unpacking a bunch of lights and doing a full system stress test