amp platform suggestions...

Yes WOW - that's why the constant caveat YMMV

The Polycrystal, Symposium Ultra and Black Diamond Racing have all sounded good for me, as do the Sistrums. The Silent Running gear is supposed to be awesome. But you are in a different budgetary league.

Also FWIW - I have seen people argue that a cutting board does not sound good unless its made of end cuts or one piece. And here I thought that wood was wood...

Like Zephyr I have noticed that certain types of isolation devices work better on certain kinds of materials. Granite is very unforgiving of brass points, BDRs etc.

Granite is excellent if your goal is to isolate your component from any wall or floor born vibrations. The Herbies units you are considering (which I have) should be a very good match. So would Aurios.

Wood tolerates most devices and many people believe it to be warmer. I think there is something to be said about having a large block of wood as a reflective surface being more pleasing then having a large piece of stone.

Beyond the maple, take a look at some of the myrtle wood platforms being offered by edensound and others. Myrtle is extremely dense.

I have never been able to figure out why any kind of block or shelf would help with airborne vibrations. I think that this is where tube dampers and mass loading come into play. This may also be where devices like the Herbies and the Aurios which allow the unit to move freely make a contribution.

For very reasonably priced granite check out grizzly dot com and type in granite in the search box

I have also ordered thick cork sheets from McMasters and applied them to the base of the granite for massloading on top of speakers.

Fiddler - for a long time people recommended - and as far as I know still use Vibrapods between two pieces of material like Lexan.