Tony, From your description, it seems you have an older SOTA tt. So far as I know, all the later SOTA tt's have eliminated the very real problems inherent to a belt-drive design that mounts the motor on the chassis while suspending the platter and bearing. (You've described them well.) You might consult SOTA and let them "fix" it or let them tell you how to do it.
In the 90s, I lived for many years with a Star Sapphire Series III, which is built their "old fashioned" way, with motor mounted to chassis. I thought during that time that it sounded "pretty good", but I was not yet a total analog nut job, as I am now. Words cannot express how much better analog can get compared to what that SOTA SSIII gave me, in retrospect. Even my next tt, the Notts Hyperspace, with its stretchy rubber belt and weak motor, just absolutely killed the old SOTA in terms of pitch stability. The Lenco and all of my dd tt's take that to yet another dimension, adding more drive and open-ness to the music. You've gotta try it. Timeline, Shmineline.