Thanks Guys, for all the useful info. I`m leaning towards the glass window, I don`t mind the limited visibility, I usually use the side mirrors when reversing anyway. Probably I`ll wait with this investment until spring though. First, what I`d like to try, is to buy similar vinyl material and stitch it in place the old one. The rest of the top is in perfect condition. It`s a lot of stitches, and it may end up being a complete waste of time, but I thought I`d give it a shot.
I found this on ebay for cheap:
https://www.ebay.com/itm/Clear-Plastic-Vinyl-Upholstery-Boat-Auto-Window-40-GAUGE-54-Width-BTF/331956509141?hash=item4d4a2659d5:g:OjsAAOSwpDdVU5Y G