masi61 - Greetings. There’s been no response most likely because there’s no safe answer. Everything depends on everything, and your room dimensions, absorption, damping and losses interact with the floor coupling. I, too, await with interest any observations from those experimenting with GAIA feet.
I can tell you how we approached the matter at Thiel (early days / first 20 years), which may have changed, but not too likely to diverge radically from the following.
Speaker development occurred both in the lab and under multiple test conditions. In other words, we did not tweak for or against any particular coupling conditions, since those are so complex (as stated above) and unknown, to be counter-productive to project or assume. Bass target was .707. Baffle step (progression from omni-directional to directional propagation behavior) was first calculated and then verified multiple ways: speaker hanging in free air, speaker on pins on a solid, non resonant surface, on a solid elevated platform, buried in a sandbox, and in at least two listening situations - all under measurement and critical listening.
Over time we learned to correlate these conditions to shape toward our target .707 x -2dB bass shelf in anechoic free-space. Our surfaces were these: Outdoors was A) flat roof with rubber membrane roof over hard foam insulation on deck = highly damped and non-resonant. B) parking lot with asphalt over packed clay (heavy truck surface) which is also non-resonant. Mic positions were overhead, ear-height (floor bounce) or ground-plane (no floor bounce). Note none of these has any reflective / reactive coupling component. The sandbox puts the speaker on its back, firing up with baffle edges flush with the ground plane (no diffraction). Alternately the speaker is in the lab wall in a quasi infinite baffle. Comparison of sandbox to wall-mount lets us see cabinet vibrational effects and leakage losses as well as edge diffraction effects.
Indoors had two major environments: A) the farmhouse had stiff hardwood on joist construction with very little bounce, but significant bleed which differed with and without spikes. (Oak floor on hard southern yellow pine subfloor over SYP joists) 1903 Victorian Farmhouse. We treated spiking as a way to effectively eliminate enclosure recoil / sway, but ignored tonal additions / subtractions as arbitrary. After 1980 the lab was moved from the farmhouse (which had incorporated a cross section of the previous elements, to industrial space in a second floor, wooden-floor space, then two subsequent concrete-floor spaces. The concrete floor was industrial freight warehouse spec. The factory purpose-built music room had that same slab floor topped with glued-down industrial hair underpad and tight wool / jute-backed carpet for a very quiet noise profile. (A 10# iron ball drop did not ring).
We also took every speaker in development back to the original farmhouse living room which produced a warmer, fuller room sound than any of the lab or factory listening environments.
Of course there were show environments, which we took as they came. And we received criticism for rarely tweaking the room or floor coupling for ’best’ performance. We used shows more for dealer and reviewer engagement rather than showing off the highest performance of the product.
All this is by way of describing that there are many, many interacting variables with little to no way of predicting how your variables will stack up against neutrality or your tastes. A particularly tricky business is separating room modes / placement issues from floor coupling / leakage issues. Have you used any of the dimension calculators to assess your room issues? You are welcome to post your dimensions here if you wish and I’ll respond with first-pass performance comments.
I have no experience with any of the commercial isolation / coupling products. I have learned a little from show setups and local installations. With the stock Thiel pins you can effect their floor interface by using blu-tac or mortite in the sockets and/or under the round end at the floor termination. On a carpet you can tune the interface by how hard you force the points into the carpet or whether or not you put anything under the point (rivet, washer, penny, checker, matchbook, etc.) Historical note, the later, wider stock points with 60° included angle do not readily pierce the carpet,but they do concentrate the load well enough to minimize cabinet recoil. Using these simple, free approaches, you can get a pretty wide range of isolation / coupling with various floors.
I realize there’s very little practical guidance in all these words, but practical advice lies beyond my ability to comment. Hearing some GAIA comments might shed some light.