Improving a stone rack

Yes, good advice. I have them adjusted to a third to half compression. I use three feet under the lighter components (Teac, Hanss) but the Io power supplies need four feet to avoid cabinet stretching I think. I will soon try them under my MA1 amps, three feet should be enough. And yes, of course, directly from the chassis, not below the existing feet. Adjusting feet position to get the best balanced load from the component.

Straight up aluminum - interesting suggestion. Reminds me of how I tried to dampen the 10 kg alu platter on my record player, and found that I preferred "real" to "pleasant" - no damping. So platter mats and DIY platter damping were dropped.

I run my 20mm oversized aluminum platter on my 401 turntables naked. Real over pleasant!

I read somewhere that Duke Lejeune of Audiokinesis wrote about damping - "as little as we can get away with", or similar- in the context of bidirectional speakers, like I have. This type of setup makes the wall behind the speakers even more critical, and the ideal is a well distributed spectral tonality and a proper time delay before the reflected sound from the backfiring drivers. So, damping should be limited, and mixed with diffusion.