"Creating a Supporting Structure for the System and then working with support for individual devices will enable systems in use using the above influences, to be tuned to meet ones personal preference for how a Color is able to influence the end sound produced."
I agree with your thoughts. My racks are very solid and stable on their own so the supporting platforms and footers may provide nuanced variations or colorations reflecting the individual materials and design. In the case of the heavy DAC where I have used the wool felt, there are two platforms under that DAC, the very stiff BDR shelf and beneath that the constrained layer Z-slab. The wool felt isolates the two platforms from the stand. I suspect the density and thickness of the felt material also influences the resulting effect. The felt I used is quite dense and firm, probably similar to an F5 or maybe F7 (although the source did not provide the rating), and is a full one inch thick.
The actual footers under the DAC are currently platinum silicone hemispheres operating within the suggested weight range, so those probably provide an elastic spring-like effect. I may try different footers such as felt pads as discussed by @helomech or maybe one of the stiffer options from Herbies since I have quite a few of their products around here. The footers that came with the expensive DAC were basically bog-standard aluminum footers you can purchase from Amazon so I am interested to hear whether other materials will have a different sonic effect.