Nice design! It looks really cool.
My only grievance is that there's a little edge protruding from the back of the case which I had to remove to get the Pi in, and one of the pegs that hold it in place broke off. Still, everything sits snugly and secure.
Tolerances turned out okay on my Ender 3 with default Cura settings and a 0.3 mm nozzle. A snug fit for the Pi, and plenty of wiggle room for the 2020 mount.
I'll get some M2 screws tomorrow, but at least the screw holes line up nicely.