I have built many variants of a Support Structure for a TT.
My experiences of trialing different materials has created a method for producing a structure that always utilises Granite as the Base Tier, I have no concerns if this Tier is seated onto a Cork Pad, I have found the use of it has a attractive influence when used as a footer in a variety of situations.
I have always achieved a set up that if totally satisfactory by using a Two Tier Sub Plinth as the minimum, built of a rigid structure. This has been the preferred method over other options, such a Wall Mounted Shelf and suspension of the base platform from a Wall Mounted Shelf.
The use of Granite as the lowest tier is in my view a very good place to build from, and will be a good place to initially seat the TT.
Do not overlook the need to have a rigid structure under the Granite.
Also keep in mind that your environment selected to set up your TT is unique, energies transferred within it, are most likely not the same as any other TT users environment.
Methods adopted to control energies transferred within the environment, will have a impact unique to your situation, being inquisitive about the choices available can bring great benefits, over time, a lot of different materials can be experimented with for almost Zero Outlay and a very attractive mounting method can be discovered.
My Cabinet Floor Standing and Stand Mount Loudspeakers when used, are always on a Two Tier Plinth, with Granite as the lowest tier and Kitchen Worktop Chipboard as the upper tier, with Spike Separation.
The Speakers are seated onto a suspension footer. I know chipboard as a upper tier has worked very satisfactorily with my TT mounting method in the past.