I'm in the process of final sanding on one I picked up years ago - it was framed up - I only had about 8 areas that needed repairs / updates. I think this was the first giant scale plane the original owner did. The side windows are just cut pieces of clear plastic. I framed the windows up same as my 1/3 scale BUAS Cub.
The main windshield is a fairly slick set up. Rather than try to describe it here, I will take a few photos when we get home and post them - along with the description that will be easier with the photos. If you can find the same clear material that I have with mine, it will be an easy fabricate and install.
Dan