Since it's not available anymore, here you can find a 3D file for the High Beam Switch on Supernova Lights. For 22,2 mm handlebar diameter.
The magnet is ⌀8 mm in diameter and 2.5 mm height.
I still need to print this and test it out.
MSH-MT.stl | 691.3KB | |
MSH-MT_v3.f3d | 280.5KB | |
MSH-MT_v3.step | 212.3KB |