On version 1 I thought I'd see if I could create a "fiberglass" mesh out of drywall tape and 2-part epoxy.  The idea was to save the original back plate and re-engineer it.

Things weren't looking too bad. But they didn't get any better. This idea was scrapped.

I ended up using some plastic conduit covers I had. I cut, sanded, and polished them to fit. Not too shabby.

Version 2 will be better