My opinion is the repairs can only be done properly if the sashes are taken out. Trying to do it in place risks breaking the glass and that's a deal...
I have no experience with SW's Water White CV, or any solvent based finish, sorry. GF's Enduro Clear Poly is resistant to short term exposure to most...
I've put TT in General Finishes EnduroClear Poly and High Performance satin a few times to adjust color. Never had a problem with it being speckled,...