I am back until Monday, will be bouncing around in the Gulf of Alaska commercial Halibut fishing, wish me good weather.
Yesterday I tried springs and O-rings, IMHO they do not create enough pressure, they allowed the damper to spin on the tube. The SS hose clamps are the only things thus far that tightly clamps the damper to the tube, i.e. no spin; since the object here is to reduce vibration, I assume that this is the best route to take. The hose clamps also seem to reduce or eliminate the thermal horizontal expansion of the teflon rings, the rings and clamps due get quite warm.
Next will be machining of the ring to accept a SS machine screw for tightening the damper, should have the same effect as the clamps. I like the looks of the clamp over no clamp and the looks of the 5/16" clamp over the 1/2" clamps.