I can pass along my experience since posting. I started with furniture sliders and the difference was immediate in a cleaner sound. I then got the Big fat gliders, four for each speaker and removing the spikes, and the sound improved that much more, even though the speakers still touch the carpet. I did play around a bit with where the gliders were placed for leveling the speakers in both directions. I highly recommend decoupling. The spikes would mean a little more height overall, I think (without checking Herbie’s site), but gliders are easier for moving and fully decouple.
I’ve used the little dots effectively under smaller speakers on stands, such as Quad 12L’s. If those might fulfill your need, message me as I may have all or most of a full set no longer in use.