Modern sanders are so much better now, they get that perfect finish without the crazy time sink. Speed matters on real jobs where the clock is ticking.

My Vermont cabin had the same damp chill before we upgraded to R-40 spray foam. You're right, local weather is everything for picking the right stuff.

Yeah, I read somewhere that epoxy can hold for a bit but doesn't stop the stress... the glass is already weakened, so it's really just buying you some time.