Hi Prof - I can't see the link in your post - have I failed an intelligence test
My simplistic view of t/ts is that we have two units, and two sources of vibration; in PT terms:
Subchassis; motor and bearing
Plinth; traffic, neighbours
We need vibration sinks for both these units. For the subchassis, we reduce the vibration sources as much as possible, and (as in the PT Anni and Vector) use the bulk of the subchassis material (balsa) as a vibration absorber.
We can't control external sources of vibration, so we should build stands/shelves/plinths to absorb or reflect away as much as possible.
The connection between the sub chassis and the plinth should allow as little vibration as possible to travel from plinth to sub chassis (most likely in either direction) and should be damped to avoid feedback loops.
I guess if you want to go the sand/lead shot route, then a rigid t/t like a Vector or Saffire would be the best 'sub chassis' to go on top. I wonder what Arthur's 'Kinetic Cradle' was going to be?