There's already a system for sub-ICAO gyroplanes and light helicopters. The certification standards could reasonably be adapted. For anything intended to do aerial work or carry passengers, that's the standard they should be applying.
For something single place - I'd set a weight limit similar to that for SSDR, and let people get on with it. It's pretty obvious to anybody that these devices are potentially very dangerous - therefore anybody wanting to fly one can reasonably be left to decide what risks they want to take, and to work out how to make it safe enough.
I can't see that a solo experimenter needs state interference or protection in this case.
G