avdesigns - You might consider starting a new thread in the analog forum for feedback from members with more experience with your particular turntable - but given that you can't hear any difference with the sorbothane pads, I will say this:
If you want to tweak and try different things, that's great as long as you enjoy it - that's part of the fun - but be careful and realize that upgrades and tweaking can become a slippery slope and I've seen many here spend more in "upgrades" than on the actual device they're trying to upgrade (with cables, isolation platforms, platters, weights, etc. etc.)
The fact that you can't hear ay difference with the new sorbothane is a good sign- shows that you aren't all that susceptible to "wishful thinking" -that's a good thing.
You have a great table for the money, you should enjoy it and if you see a problem and you can fix it? Go for it - otherwise, don't go chasing your tail unnecessarily - your Music Hall should deliver great results as-is and if you think that you have isolation or resonance problems, chances are, the solutions aren't going to ever be solved by some silver bullet "tweak".
Just my $.02
Greg