It's interesting what your findings are Heinz. I've been a bit concerned about the firm ride over bumpy surfaces (thus the reason for starting this thread). I checked yesterday on my bump stop clearance and I cannot push my little finger between the axle and the bumpstop when I load the car with my weight (65kg). So thats about 8mm which doesnt seem much. The ride can certainly be jarring at times. I might look at reducing the bump stop height as you have done.
This is the guidance I recieved from Peter Ballard
Jack car under the middle of the front lower cross tube on the front frame to lift the front wheels just off the ground. Unladen, feel the gap between the axle and the rebound rubber between it and the chassis. Gap should be about a finger thickness (easy to feel) or about 10mm to 15mm. Should be the same both sides within reason.
