Halcro, Yes, that is a plinth. I like the idea of removing the chassis cover below. It looks cool, too. I think this set-up, along with your extraordinary tonearm pods, has the Lew seal of approval all the way. (Your pods are so solid and heavy that I won't carp about them, especially since the materials of the new plinth are similar to the materials of the arm pods.) I've been thinking about something exactly like what you have, EXCEPT I would have a firm linkage from arm pod to main plinth structure, and the arm pod(s) would therefore not have to make contact with the shelf.
I acquired some very heavy thick elastic bands which I was going to use to damp vibrations of the chassis cage that you've entirely removed. The only issue you may encounter might possibly be that the cage shields against RF.
May I suggest that you listen with and then without those rubber isolating grommets? I would be very interested to know what that does.
My TT101 has had a frustrating history. It had to go back to Bill Thalmann twice since the original re-cap was done. There is nothing wrong with any of the ICs, but Bill finally figured out that several of the PCB tracings and a few connectors had developed cracks causing intermittent short circuits, which led to crazy behavior of the mechanism. (It would work properly at Bill's shop for days. Then because the drive to my house is over bumpy roads, I guess, it would do nutty things in my house.) I've now got it home finally and all is well, after Bill sniffed out the problem areas. I do have a bunch of clock chips for anyone who has a Victor TT with a bum clock (Part #SC3042, made by NPC). (The same chip would work for TT81 and 101 and possibly for 71.) Mine never needed it. Contact me privately. They are cheap.