I've asked this same question both privately with some others, and also I believe publicly here.
I didn't have any success with numerous Forum, or Web searches, nor did I have any luck contacting Audioquest, or Sumiko to even get information of what cSt Viscosity the Damping Fluid was? All Audioquest offered me about 6 weeks ago, was a 1/2 dried up last remaining little Vial. There was also no information on said Vials either, so that offered no help.
About the only people I hadn't contacted, was Jelco in Japan, the folks who manufactured this Arm. Oh, the other people I never contacted as well, was Graham, as I believe the Graham Robin was manufactured by Jelco as well to thier Specs.
What I recently did, was ordered two Vials-Styringes total of Damping Fluid from Turntable Basics. I ordered one 10,000cSt, and one 30,000cSt Viscosity Silicone Tonearm Damping Fluid.
While I have yet tro try them in my own AQ Arm, these seem to be about the best bet. They can be used straight, or perhaps even blended?
As one friend suggested, lighter weight viscosities is probably better than a too heavy viscosity.
Hope this helps, perhaps you'll have bhetter luck from the folks I didn't contact about what cSt weight would be ideal? Mark