Yes the steped pully drives the idler what you are not seeing is that when you ingage the speed selection that selects the appropriate step in the pully and forces the idler against the lip under the iron sub platter.
The main sub platter on the first version is iron, not aluminum. The upper platter is. The idler contacts the underside of the sub platter. It is always best to clean the idler with alcohol as well as the contact rim on the sub platter.
The TC-50s were not great speakers if you were expecting a lot if bottom. Fantastic in their element, vocals, jazz. The TC-60s are better, rear porting helps, as does the larger enclosure. I to tried the l-05s and felt the same way, it was just ok. Both the TC-50s and TC-60s need to be far away...
I think for the Spica TC-60s the L-07M is the way to go. The 9s are overkill. I had a pair of TC-50s as well. The 7s worked great there as well .I am used a L-07CII preamp. The 9s do work well with my B&W 804Ss
I think adding mass is alwasys good. I used Dynamat on my KD-500 but I had a little bit of trouble getting the platter balanced.
I think my 124 weights in close to 50 pounds, maybe more. Slate plinth and armboard with the Tenudo platter mat. Woodsong bearing rebuild , audiosilente idler. Rebuilt...
The L-09M and L-08M in good condition will be the hardest to find. Followed by a good clean 700M .
The L-05M and L-07M show up frequently the higher speed L-07MII has some issues. Sonicly I have found the L-05M and the L-07M the most accommodating. I have not owned the L-08M.
My personal...
L-05Ms, L-07Ms, L-09Ms, L-07CII,L-07TII, 700M and 700C, KD 500, Yea , I guess I am a Kenwood hoarder..They sound great. Fantastic build quality. Good clean units are getting hard to find and a bit costly when you do.
Its a good table. Several upgrades. Better armboard, acrylic platter. For starters. Clean and relube the bearing before you use it. New belt might be needed as well.