To lewm's point:
The 'bearing' in either the original WT arm or the WT Reference arm or any of the current WTLab arms amounts to an arm tube and paddle assembly suspended by two mono-filament lines (fishing line) which are immersed in a cup of silicone fluid. This assembly acts as the
'pivot' point. I think I determined that having a Koetsu Sig, is more the culprit than the arm, reading several other commentary on this cartridge and going to Koetsus which have platinum magnets will make a difference in bass output.
To m-dB's point:
I remedied the WTT concave platter issue by going to my local hardware store (Do It Best) and spending a grand total of ~$1.29 (?) for a rubber (pliable) disc about the diameter of a 45rpm adaptor and ~2-3mm thick which just happened to fit perfectly in the center silver spindle area of the platter (on Classic table). No cutting to size required. This effectively elevates LP label to just at (or VERY near) the same height the record is at at the outer edge of the platter. Consequently, when I tighten the record clamp down, the vinyl is not oil-canned in at the label area (which would cause skating problems otherwise.