Now that I had proved it all worked, it was time to design an enclosure and make it real. I used Fusion 360 to design it and then 3D printed the enclosure. The design heavily draws from the commercial version, but I don't intend to sell these. This is just for me and their design seems good enough.

I made the lamp holders tilt down 5 degrees. It seems about right, but might be worth tweaking later.

I had to modify the reflectors to make them fit in the new enclosure. Luckily they're made from very thin aluminum which is easy to cut with a pair of scissors.

I cut the sides first and then shoved the reflector in the lamp holder, marked the edges, and cut them to length.

Here's the finished product:

One thing I was concerned about was the heat. Running the lamps on low voltage means they don't get scorching hot like intended, but they're still warm. After running the heater for ~30 minutes the lamp holders started to get soft on the top. I measured the temp with an infrared thermometer and it was about 120 F. Just enough to make the PLA soft. You can see a slight bulge in the top of the lamp holders in the pictures. I made a quick fix by bending the reflector away from the top and bottom of the holders, and that seemed to help. I'll probably get some PETG or ABS and reprint those pieces.