Fiberglass door/window guidance needed

At least you started with a pattern, when I bought my Demon with the 'glas doors, I had nothing to work with. The previous owner had glassed over the slots for the windows so I had to make brackets that bolted to the top of the doors. From there, I made a pattern for a one piece window & bought a 4 x 4 sheet of Lexan at my local home improvement store, along with the correct cutter & went after it. Mine are not perfect, but they are good enough for my bracket car.
Oh wow! Wonder why the po would cover the window openings? So he didn’t run windows at all? Glad to hear you found a solution though, I bet it works just fine.

I have seen some cars with the metal frames for the lexan windows and they look just fine, I just thought I’d try the preformed route and hope the existing door hardware fits it and if it still rolls up and down that’s an added bonus. I just need them to seal halfway decent and not be loose and flop around so much as the passenger side does now.