@atmasphere You are correct regarding the damping ability of vinyl due to its light weight. When I was experimenting per my post above, I recall leaving the rubber mat on the platter which effectively damped the ringing of the metal platter, then using a vinyl LP between the mat and LP I was playing after adjusting the tonearm height slightly.
Herbies sells these rubber dots, 2" in diameter and a thickness of maybe 3 or 4 sheets of paper (so very thin), and seems to be made out of cloth impregnated neoprene that has very effective damping characteristics. I suggested he make a turntable mat out of this stuff but never heard back. I thought it might work well on my Linn in place of the felt mat.
