Looks good, and I take it is sounding good, so great result. To answer some of your questions based on what a chum of mine tells me (who incidentally produces a belt drive turntable using his patented vector idea, which doesn't create that pull you refer to, although I don't think bearing strain is the primary reason for it - I'm not sure what the quoted service interval on a belt drive bearing is but there's a few that have gone round the clock, and the thrust surface usually wears first).

You are quite right - balance is unlikely to knacker a bearing. It is however quite important to the turntable - the good news being it's nothing special on the standard platter. The effect of imbalance (much more so than mass, or even inertia, within limits) is to put a strain on the servo mechanism (which IS the idea behind vector). For this reason Technics engineers dynamically balanced the platters on the SP10 - issuing a "balance passed" sticker for them (which presumably promptly put them out of balance again - we split hairs).
Damping often improves results but can be unpredictable. It was clearly the solution chosen by the Technics engineers originally, although, as you have demonstrated, not all that well done. However, it is not a panacea. I remember a prototype platter Arthur built our of MDF - about as dead as you could wish for. Not a happy experiment.

Bonding a mat to it on the other side of course also damps it to a degree. I'm continuing to enjoy my own newly acquired Technics record playing device. Happy listening