using rehd's rubber band solution, what about a single flat elastic length attatched on the face of one cam going around and back over and around the other cam. attached on each end portion only. iff the elastic was real stiff (maybe even rubberized webbing), you could push hard down on the clamp and the band would both stop cam slipping as it is trying to rotate the cam and provide elasticise pressure on the 2 strips or whatever the overlap is.

if the webbing or elastic was flat on the ctr, maybe could add a wedge or cone to add pressure, but the web or elastic is prob good enough. issue would be how to release. maybe if the elastic was deflected sideways, or a cammed bead, or the web could be in 2 parts w/ a snap or buckle or velcro on top for release.

could maybe twin the housing w/ thinner mat'l to keep forces ctred on the pivots

if you do a new configuration, its gotta be your show!