A scan of the parts book showing the guts of the regulator:
I was extremely fortunate - the parts package I originally bought had a good regulator in it. Shortly afterward a NOS regulator appeared on eBay. That is the regulator I used on the car, and I kept the original for backup/parts.
The black button on the control housing sets the unit. It grounds against one of the housing attaching screws, completing the circuit and locking in the regulator, which is then held in place by the magnet assembly. Up until you push the black button, it is just a speed-minder, exerting back pressure on the accelerator pedal, unless turned off. Once locked in, turning the thumbwheel to off, or tapping the brake pedal breaks the circuit and turns it off. There is also a page in the parts book showing pedal switch placement and wire routing.
Operating instructions to follow...
Paul