I had posted asking about which was better and verdict was foam, but now that I'm pulling fiberglas that was packed in tightly by DH, and Dow says don't get Great Stuff on finished wood window sills, I'm wondering whether it's worth it?

I started on window over kitchen sink and it looks like I'm pulling out stuff from over the header now too - do I need to pull out every shred of fiberglas from around the framing, without getting it out of the wall around? Or can I foam over *some* (like the original pink builder's stuff) FG if I just pull out what DH put in?

Should I just leave the FG and put up the casings with some caulk behind to reduce air infiltration? Try to pull some out and "fluff" what's left so it's not packed in like DH left it?

It's such a mess - and I want to get these remaining window casings up. All the upstairs ones are in with tightly packed FG - DH says we're *NOT* pulling the casings off to redo insulation. Does it matter on the downstairs at this point?