This BLTouch mount is designed to be solid, such that the BLTouch will not change position, even under significant stress -- accidental or otherwise.
Mine is printed of ABS, for the higher temperature stability, though I think PLA would be fine too, given the cool air fro the extruder fan.
Holes are such that M3 and M2 self-tapping screws are used. The M2 holes are on the underside, for the BLTouch itself.
Two 3mm holes need to be drilled into the Sunhokey Prusa i3's plexiglass, as you can see from the photo. Simply use the printed bracket as a template for those first, at 2.5mm for the self-tapping screws. Then drill out to 3mm.
The attached CAD file is a Fusion 360 Archive file. Upload to your F360 cloud account and use as desired, according to the CCA licence herein.