OK, I am getting interested in trying this out - another possible use for magnetic hold-down in on two wheeled vertical spinners. Imaging being able to turn sharply without gyro dancing! If I can get that to work on my new spinner bot, it would be a real game changer against most other designs.

How do people think the hold-down force can be tested on the bench? I have a number of salvaged NIB magnets, several electronic and mechanical scales, lots of junk to make jigs from and a short attention span.