You can't easily get Herbie's products here in the UK so I make do with sorbothane or similar.
However, everything I've read about them seems to make straightforward sense. On a solid floor like yours they may be less effective than say on a suspended floor, but it will still depend largely upon the way your speakers have been constructed.
I use them with my Vandy Treo’s. I use them to protect my wood floors. I can’t say that they either help or hinder, as I would not put spike marks in my floor. They also help with moving and adjusting the speaker as they glide easily. FWIW, I’d be worried if those spikes could put a chip or make a crack in travertine. Bob
Use Herbie's cone/spike decoupling gliders. They work very well in isolating the speakers so they don't vibrate the floors. I also use them under my rack to isolate from floor borne vibrations. They will also protect your tile.
I added the Decoupling Gliders in brass a few months back to ride under the 3 spikes per speaker. I felt that they brought a nice touch fullness in the lower registers without losing musical definition, and the mids up seem a bit clearer, too. And they make moving my speakers a breeze, so for the money they are a great addition to my TAD CR-1's (which like getting more fullness down there).
I am curious to try the IsoAcoustic's Gaia's for comparison to see if they take these musical qualities further.
as I recall OP has 5a. I have used the Vandersteen spike shoes with five A, 7’s and the amps which are also spiked on both tile and hardwood to good effect. they are machined w felt and fit your cones, reasonable for made in USa, available thru your Vandersteen dealer
I use Herbie's gliders under my Wilson MAXX speakers to be able to move them on a hardwood floor. The use of the gliders did not change the sound at all. If I place my hand on the bottom of the speaker when played loud, I don't feel any vibration whatsoever due to the cabinet material and their weight, so that may be the reason they did not change sound. I really like them and recommend you give them a try; my guess is you won't send them back.
In regard to JTCF's post above: I temporally used 8M carriage bolts with my Focal 726-floor standing speakers (two months) while I waited to receive my custom 8M spikes. As soon as I installed the spikes I noticed an immediate improvement with dynamics, sound stage, and bass. I believe you don't know what works until you try it.