Which cone's or platforms have helped?

I have tried numerous setups over the last 20 years and the Walker Valid Points/Discs are the best I have ever heard.

Most experts regard cones, pucks and the like, as relatively minor players, compared to shelves and platforms. I looked for many years, for improved vibration isolation, and tried many products, and I've stopped now, completely happy with Neuance Shelves. At $150-$175, I regard them as one of the great bargains in audio today. The only caveat: they need proper support from below, spikes being best. Ken Lyon will advise on this crucial aspect of performance.

Put cones under everything. Your ears will be very happy. If you don't have them, already, on the bottom of your rack legs: PUT THEM THERE too. I have not compared them, but I use Audiopoints cones and am very happy with the sound. You can really go nuts with these cones and suffer the law of diminishing returns. Call Robert over at Audiopoints. He's really into resonance transference and will give you the scoop. His cones are very reasonable. You should get another 10 posts, at least, about this topic. The same people, including myself, will talk about this adnauseam...I love it, though. It's what I love about the Hi-End audio game.