I don’t weld either, and I’m never going to. I think people just screw in washers to close the holes. My question about a stainless steel circle was about making the diameter a bit larger, and I was imagining doing that with a nut and bolt through one of the holes. I totally confess to being pretty clueless in this area, so I have no idea if that’s possible or safe. That’s why I asked. Members like
@bholler and
@brenndatomu are much more qualified to advise. I can just ask.
I completely understand why you’re feeling stressed. The good news is you’re past the hardest part of winter, so you’ve got time to get it figured out this spring and summer, and you’ve still got some cold now and the Regency installed to see how draft is affected when you change parameters according to the expert advice here (not my advice, that is). I’ll just try to offer moral support when I can. (It’s kind of a joke in our house when I’ve dreamed up some way that my husband is going to repair something or install something that I’m on standby to hand him tools and offer moral support.)
Edited to add: It looks like you replied as I was typing my wordy response. Maybe the guy you talked to about the custom surround would have some ideas.