Parking lot speed bumps work well for ballpark settings. An external observer is a big help.
Start full soft. Drive over the bump having observer focus on one end of the car. Firm up that end until it catches the vehicle weight on the first bounce and doesn't launch that end on impact with the bump.
Do the other end of the car.
Go back to the first end and see if you can go softer with less launch and still catches the car's weight on the first bounce. Repeat on the other end.
Softer than "feels" best is often faster. Your brain attributes feeling the road with good handling, but that is often over damping the springs in one or both directions. Remember, this is not about driver perception, it is about keeping the tire in contact with the road optimally.
Koni track adj. procedure