You said, "Probes could be made with a spring that followed a K constant and the probe could also have a linear potentiometer to measure resistance to know the deflection, but the probe may not have to include the resistance if the surface scanner can also see the deflection in the probes."

I agree that this would yield a means for measuring the deflection.

What puzzles me is, "if the surface scanner can also see the deflection in the probes". Do you mean that each of the nominally 100-300 probes, possibly
the first 100 used 3 times at different latitudes along the stump, would have to be examined with some optical scan, e.g. machine vision or whatever, in each of the, say, 360 positions in the circumference? I'm thinking that this might increase the labor cost involved, rather than reducing it.

My own original amputation was at the ankle, which made for a rather long socket, as it was amputated at the ankle, with the heel pad sown in place. After the second amputation, it was only about 6 inches (15 cm) long. The former would require several incremental passes, but still with approximately 100 probes, so the bony projections could be located with reasonable precision.

RE