The non coilover/Non MacPherson strut dampers I have seen have all been adjustable 'off the car'. That is for recent cars. That is not to say that you cannot adjust them on the car. As long as you can put the damper to the very bottom of its travel and turn the adjuster it can be adjusted. The bump stop may prevent this however.

If it were me I would try going from one extreme to another and trying to find the middle ground. Annoying with your dampers for sure. but you could be guessing for a while even with reccomendations. Everyone likes different things.