Cut the makrolon for the “lens” with some newly acquired snips. Turns out metal snips are perfect for rough cutting materials in the plexi family. Random reading on Pinside often yields tips like these.
I’ve still got to figure out the bracket solution. I ordered a cutting blade for my dremel (misplaced all my attachments!) and I’ll be cutting an access for the bulbs later this week. I’ll sand out and refine the shape of the lens when I can test with light.