amp platform suggestions...

I was thinking of using some granite with some Herbies Iso-Cup/Lampblack Ball between teh granite and the amps. What are your thoughts?
Neuance-IF you can find one used. If not, I would check out some of the wood platforms available.
You must "hear" the Grand Prix Audio Monaco amp stands...superb!
I've never heard granite in this application to be successful. Granite has a ringy sound that is unmusical.
If it's a big heavy amp, consider an inexpensive concrete pad as a base load on the floor. These are sold pre-formed at the big box stores. Then use a combo of Wipuna Sound Myrtle Feet on top of 2" x 2" cork/rubber feet under the amp. Caution: Low WAF!
All materials have sonic signatures/attributes of one form or another be it granite, maple block, epoxy, etc....Granite in and by itself does have undesirable sonic attributes.

Adona Corporation addresses this and makes beautiful, sonically friendly amp/equipment stands through the use of layering of granite, MDF and a special (i.e. they don't tell you what it is....) material that is bonded together. The stands themselves are very functional, easily adjustable and aesthetically pleasing. They have various facing and finishing options available. They are also able to be re-built into various combinations and configurations over time by mixing and matching the various upright lengths and x-frame combinations available. A large part of what makes them useful is also the ability of weight the metal frames and granite/hybrid shelves are able to hold, i.e. they easily take the loads presented by large amps, transports, power conditioners, etc...

I have found the following;

- certain vibration solutions such as Stillpoints and Black Diamond racing pucks under my equipment to further isolate are not a good match with the hybrid platforms and have a sonic signature that I do not care for when used together

- Composite Audio CF-2010/similar platforms that utilize high-tech epoxy, sorbethane and carbon-fiber combinations work VERY well in conjunction with the Adona granite platforms to provide a extra level of broad spectrum vibration isolation that sounds great (to my ears)

As an aside, I've consider hard-aged Maple blocks in the past such as the high-quality ones sold by Mapleshade and others. They are a great solution.
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.
Two inch thick maple cutting boards totally bloated the sound of my system. Slow, confused, overly warm, muddy, you name it. Simply put, the maple cutting boards were terrible in my system.
WOW! It's amazing how the results have varied so much. Has anyone used a 1" thick polycarbonate as a platform?
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...
Yes, I am currently using 1/2" Lexan shelves. Best solution I have found yet. And don't confuse Lexan with Plexiglas. Two different materials.

In time I may try two pieces of Lexan with a piece of acoustic felt in between. Not sure if that will be an improvement, but I want to try it. I have lots of Lexan so it's just a matter of getting around to it.
Fiddler - for a long time people recommended - and as far as I know still use Vibrapods between two pieces of material like Lexan.
IF the object is to have an inert stand, the shelves can and maybe even should be made of layers of material which have different resonant signatures.
Granite, lead sheet, sorbothane, hockey pucks, golf balls, tennis balls, Maple blocks, Lexan and many more.

Materials and most importantly the MASS of materials can be chosen to have conflicting resonant frequencies with the result being that when put together, they are nearly inert.
I had a turntable many years ago....a Dual 1209. The platter was made of 2 pieces which individually rang like bells. Together, it was like thumping a piece of silly putty.