Lazyman
..... Now you just need to 3D print a mag switch you can add your own magnets to.  

Years ago I looked into making my own mag switches.  Looked more involved than I was prepared to undertake and they were just too big,

However, with the 3D printer. the "too involved" is taken out of the equation.  Might just be a worthy SketchUp exercise.

If your first cut is too short... Take the second cut from the longer end... LBD