I also prefer partially filled bicycle inner tube under full size components like CDP, over vibrapods. Also remove MDF sandwich and have only tube between component and shelf, this eliminates component feet. I also recommend using vibrapods between monitor speaker and stand, even though this is contrary to your instincts, many good things will happen. For skeptics try first before you dismiss this. Have not tried vibrapods under floorstanding speakers, but would not be surprised if they work great. I have tried many isolation devices but partially filled inner tube is very effective.
Isolation Devices
I would have never believed what the difference in sound a simple isolation device can make unless I actually heard the differences myself. I have a hardwood floor in my listening room and after adding Isopods under my spiked Thiels (MDF sandwiched between) the difference in detail, presence, and bass was very satisfying. I thought that the next tweak would be to add Isopods to my Cal Alpha DAC. I replaced a bicycle inner tube under a piece of MDF with Isopods. After days of listening, I tried to convince myself that my sound had improved but my ears told me a different story. The Isopods made my music sound hard and edgy. I replaced the Isopods and went back to the old bicycle inner tube and the sweet warms music returned to my system. I am confident that I used the correct Isopod models for my DAC. I'm looking for Isolation devices to impove all componets in my system. Is it overkill to isolate a power conditioner, transport or preamp? Any other devices or tweaks, do-it-yourself or manufactured? dh