AZ in Colorado Springs
I made something very similar to that, but the top can swivel down to create miters.

I put a piece of 1/2" MDF on a faceplate. Plenty stiff. I use 12" diameter adhesive backed sanding discs from woodcraft.

It works great. It's about four years since I made that. Someone commented that the sanding dust would wreck the lathe bearings, but that's not been a problem.