Let me give you a cool tip for cage building!

One of the hardest parts with a hinged door is putting glass into it. So don't use glass, use plexiglass. You can just get it cut to the size you need by the store.

Then frame your door. Or you can even just make a door out of plywood and cut the opening you want.

Then you can drill holes in the plex and just screw it to the frame on the inside. From the outside it looks like a cutom fit.

That little tip has helped a ton in my cage building, and you end up with a sturdy door that is also nice and light.