I rough cut the canopy to size. I left about 1" of "play around all the dimensions.
The saw is fantastic - perfect for the job.
Each time I make a cut, I sand it with 100, 150, and 220 to reduce stress concentration factors on the cut - I do not want to get a crack.
I am cutting this in the basement. I heated the room to about 80 degress to reduce the brittleness of the plexi. Pretty smelly, but what can you do - kinda like melted plastic (shocker!).