Cones under a suspended table?

One of my tables is an AR ES-1, which I've made many upgrades to over the years. It works well, and is relatively free of influence from footfalls, but I'm looking to optimize the coupling between the table and the custom shelf it sits on (I made it from 1-1/2" of HDF, under which is a layer of Sorbothance, and under that a sheet of granite). I've read on the one hand that tables like this work best with their stock feet (little rubber feet), but I'm not sure I believe these can provide the best transfer of unwanted energy from the TT into the shelf.

Anyone have experience in this area? I was thinking of trying Black Diamond cones or something like that in that sort of price range. I've been told Stillpoints are supposed to be "right" for suspended tables, but they're a little too pricey - given the age and relative value of the table. Looking for a cost-effective improvement.

Other things I've considered are Audio Prism Iso-Bearings or a set of spikes (generic) I already have resting in Isoclean Tip-Toe bases. I'll repeat that the TT is pretty well isolated from external vibrations; I'm looking for a way to drain unwanted energy from the table into the platform in the hopes of improving clarity and control.