If you like your Gaia footers, and plan to keep them, you might try them directly on the carpet and get the same level of performance, without the granite slab.
I can’t tell from the pictures how integrated the spikes are to the outriggers of your speakers. Assuming they are threaded, I can understand how you might feel most comfortable with footers that can be screwed into the outriggers, such as the Gaia footers. If I were using the Townshend Seismic Isolation Podiums, I would probably consider bolting them directly to the bottom of my speakers (or in my case the stands).
IME, you can get the same level of performance for less money by using individual springs, if you size them properly and damp them. The individual springs work well when your speakers already have a solid base such as the outriggers on your Reference 5s or the Sound Anchor stands that I have under my speakers and subs. This place has a nice assortment of springs and a filter that can be used to identify an appropriate sized spring based on the weight of your speakers, but keep in mind the weight may not be distributed evenly (mine were heavier in front, since that is where the drivers are attached to the faceplate). A loosely applied layer of thin heat shrink (with a couple of holes poked in it) can be used to damp the springs and improve the appearance (you can see the look on my system page).
I recently spoke with an equipment designer (not speakers) that I occasionally communicate with and he told me that some of his customers and industry folks whose ears he trusts have switched from spikes to spring type solutions with good sonic results so I am not surprised you are hearing good results with the Gaias.