Anutami, thanks foe the suggestions. I order from Amazon all the time but I’ve stayed away from aliexpress. Have you used them? Regarding custom windows, I communicated with several manufacturers. They weren’t interested. While they did not give explicit reasons I got the feeling it was due to quantity and profit margins. Tcliche, the link was removed for some reason. Could you pm it to me. I had not heard of Maygood. They have a variety of windows with differing corner fillets. The window with the 7 mm fillet would work with just adding a gap filling piece at the bottom. Another option would be to get the 900x550 and cut a little off of the camper cutout top and bottom. The wall thickness parameters look good. The frameless windows were a closer match but I couldn’t find anything on a secure site. Good luck with your order. I’m interested to know how it fits.