The GAIA III will work but I believe the GAIA II will work better. I had the same situation and paid a little more for the bigger footer. I’m happy with them.
Isoacoustics Gaia Speaker Footers
Replacing the spikes in my Soundocity outriggers (Soundocity made me a set of outriggers with threaded holes) with the Isoacoustics Gaia 2 footers has improved the sound of my Merlin VSM speakers. They now sound more open and articulate than with any combination of Z-feet or other spikes, with or without outriggers, on the floor or on a platform, that I've tried. Like the Townshend products the Gaia footers completely decouple the speakers from the floor, allowing them to float. See:
http://www.audiostream.com/content/isoacoustics-gaia-isolation-pucks#IVXH8EtVAjQdwbuj.97
http://www.isoacoustics.com/products/gaia-series/gaia-i/
http://www.audiostream.com/content/isoacoustics-gaia-isolation-pucks#IVXH8EtVAjQdwbuj.97
http://www.isoacoustics.com/products/gaia-series/gaia-i/