[cynical2]

I have started to make my masking system, but haven't finished it yet. My screen is painted on the wall, so my options were very limited. I'm just going to wrap pieces of 1/8" hardboard (cut to the right size to move from 2:35 to 16:9) iwith velvet, with "tabs" sticking off of the back of 3 sides. The hardboard is thin enough to easily flex, and my belief (hope) is that I can easily slide the tabs behind the velvet wrapped frame on the wall. For example, on the left side of the screen, the tabs will slide behind the frame on the top, bottom, and left borders (frame) that are mounted to the wall.

It's a $5 solution, and once it's done I'll report back. So far, only the hardboard masks is cut. I haven't wrapped it in velvet or attached the tabs...yet. Hopefully, it will be a workable solution, as I want to control costs for my 1st solution.