My buddy tried that exact thing with his back door last summer. He got one of those shade sails and hung it out over his deck. The difference was crazy, like walking into a cooler room right away. He said the best part was it didn't make the room dark, just took the harsh edge off the sun. He did mention you have to really secure it though, a good wind will test those mounts.

Locking rabbets sound solid for the drawer boxes, but what about the face frames? @the_caleb, do you hide those joints too or just let the glue do the work?

My first shim was a folded pizza box, which tells you everything about my skill level.