Thanks for the replies. Unfortunately I think I've discovered the grinding part a little too late. Not too much, but certainly more than I wanted.

I remembered that I have some welding shield material that I bought years ago. It is essentially translucent plastic designed to be used as a welding curtain. It is not as easy to apply as the 3M material would be, but I've been able to attach it with zip ties and duct tape and it seems to be doing the job. I did some testing with it welding right next to it and even over it, and nothing got through it. It is also pretty expensive but I had it on hand so it's "free".