This is based on the original design by PrincePitagyros over on Thingiverse. I have adapted this to work with an aluminium profile sim rig using an M8 bolt with an angle of 15 degrees from the rig.

Rotational angle is determined by how you attach to the rig.

As this is a ball mouse, it does not need a lot of strength to hold in place, as long as you don't stand on it, 15% infill should be fine