So if you've ever built with those opaque canopies (either the brown, red brown, or white ones), then you know that unless you support them in the back, they tend to bend down and get unseated with any kind of handling.
When I built the LT-9, I was specifically trying to avoid that issue, and I happily discovered this simple solution.
A similar problem occurs with the large wedge windshield, only this time from the opposite side. It's difficult to build something that supports the darn thing without having the supports be either a) large and bulky, but strong, or b) shape conforming and hidden but weak.
Adding in the cheese graters at this specific location provides a solution, as it allows pressure to be put on the opposide side without having the underlying structure collapse, since the graters contact the wedge almost exactly.