These are mounting plates for using ½" EMT pipe to make your prop more rigid and easier to install on your display. I recommend PETG or ABS for their thermal resistance since these will likely be outside. Here are my PETG settings
Print 2x Mount A and 2x Mount B
245 / 70
3 walls
40 mm/s print speed
8mm brim so PETG does not warp
50% fan starting at layer 4
Support settings!!
Normal
Everywhere
80 deg overhang angle
I think this is perfect because it gives you support at the trickiest spot at the top which is really the only place you need it.