I managed to get my windows put in. First I tried some kind of plastic glass from Home Depot. It was difficult to cut the curves so I tried a jig saw with a fine tooth metal cutting blade. It cracked. Went back to Home Depot and got a sheet of 3/16 Lexan. It cut very nicely with the jig saw. No cracking. My windows were attached with 1/2 rivets. I didn't try to pull the nail all the way through the rivet with the rivet gun as it may crack the Lexan. They were pulled snug and the nail was clipped of flush with the rivet. Hope to get through with this by May so we can get some camping done this summer. Pics to come.