Shamelessly copied Allan's idea to replace the old embrittled fixed ports on the cabin side. First got new 1/4" plexiglass cut to cover both openings then primed the bond area with 3M 94 Primer then applied a 1" wide strip of black 3M VHB .. Took off old frames and glass and cleaned and sanded then black-painted anything white that might show through the glass; then primed the bond area on the cabin side. Hot glued small blocks to the cabin side to guide the plexi into position since there is NO movement after the tape sticks.. Stuck the glass down then removed the blocks and hot glue remnants. Masked and then caulked all around with black Dow 795.. I am happy with the outcome.. The old nasty two windows and frames on each side are now one.