To everyone who has commented that they don't want to cut the corners on the plexiglass: I completely agree, that's a crazy pain in the ass. I feel your pain.
Let me make an observation that should be pretty obvious, though: Instead of printing the top brackets, just print another set of the bottom brackets. Then the bottom front right can go on the top front left, the bottom front left can go on the top front right, and the back brackets are interchangeable. Then everything lines up, and you get a little bit of extra height.
In fact, it's so obvious that, looking at the Makes, a user by the name of Pboek already did it.