So, Ken, why isn't that project finished and what might you not like about the behemoth you built? Maybe that could lead you in a good direction. None of us have your skills in the first place. Many latter day belt-drive tables have virtually done away with a formal plinth and sound great. It seems based on word of mouth that idler- and direct-drive turntables do benefit greatly from a heavy, dense plinth intimately coupled to the motor/bearing. (But there are guys who like the Technics SP10 sans any formal plinth.) My own experiences with slate are in agreement with the idea that slate is very very good. (I have now made or had made slate plinths for Lenco, Denon DP80, and Technics SP10 Mk2.) But I would never claim slate is categorically "the best". Moreover, there are several different kinds and densities of slate, even within the US. For example, Vermont slate seems denser than Pennsylvania slate. I have no idea what that might mean. My SP10 plinth is made from Vermont slate.