Sorbathane under granite slabs for speaker bases?

Thank so again for the replies everyone,

Does anyone know what Herbie’s soft fat and thin dots are made of? It seems there is a lot of advice here to avoid sorbathane but use his products. Wouldn’t they have a similar effect? I don’t mind supporting him at all I just want to make sure I take the best path. My KEFs did come with the spikes and the brass gold feet. I’ll try both the spikes and just the gold feet on granite to see what works best. I’m still wondering what/if anything I put between the granite and tile. I wish I didn’t have to hollow tile shelf but at this time I have to work with it.

If you go over to "Audiocircle" that website has a group discussion devoted to Herbie's products best uses/applications. As far as similarities between Herbie's products and sorbothane, I suppose they are similar in that they are both viscoelastic materials. However, Herbie's products are mixtures of different silicones and fillers and have physical properties that differ from sorbothane. 

What Herbie says his products do, they do .

In my all-Naim system the best and the cheapest upgrade was Mana Acoustics stands for SBLs. Speakers sit on a light platform which is "floating" on the set of spikes going from Mana frame to the platform, and four more spikes face the floor. So, I cannot figure out if SBLs are coupled or decoupled from the floor, but the end result is truly magical!!!  Heavy granite slabs just lower the resonant frequencies, something I am trying to avoid in my professional business when doing microsurgery under x200 magnification.
My say: four spikes from your slab toward the speakers, four more toward the shelf. Then substitute granite slab for Mapleshade piece of maple. 
Herbie LP mat worked marvels on my Sondek, also keep in mind that I am seriously biased towards Naim/FlatEarth sound... ;-)

Try Townshend Audio Seismic Podium......these are customized to speaker weight and I believe are right up there in terms of speaker isolation solutions....I haven't tried them myself but those who have swear by it. I have a pair on order though.......

cheers