The material I used is VERY thin. Probably less than 5lbs for all the windows. It’s got scratches but consider the use. it’s gotten a lot of use and has held up just fine.
Thicker leaxan for a moonroof will work fine. You can even get colored material if you’re worried about yellowing.
Make the longest cuts with a carbide blade mounted backwards. That is to say mount it with the teeth rotating the other way(round blade here). If you’ve got access to a band saw for the corners, great If you’re careful and don’t get too agressive it won’t chip. A belt sander will round and smooth the edges for you.
Great Lakes has a scrap bin up front, see what they have there. If you want to pay, they’ll cut it for you.