Nice way to attack a problem and come up with solutions Ross. Always appreciate seeing you train of though as things evolve.
I'm always interested in the mechanical side of things. With these clamps I was glad to see you using the PVC bushing approach (like with your tilt table) to take care of the big friction points.
With this iteration, are you concerned about the cam digging a groove into the sliding block? I was wondering about a strip of HDPE drawer slide tape at that point. Of course that could cause trouble if the cam then decides to not hold position and slowly self-release.