This is a 3D model of Jack Humbert's Plank Keyboard top plate. (https://github.com/olkb/olkb_parts/blob/master/planck/tops/TOPGRD50.dxf)
The screw holes are
...Show more ~2.5mm as 2mm screws are the standard for the OLKB cases. This topplate should work with the low profile and EOTW cases/bottom plates.
This model should be identical to Jack's 2D dxfl file, but is 1.5mm thick which is the standard for MX style switches.