The alternative to kilopoise that Refugee mentioned is high viscosity silicone oil that is used by the model vehicle enthusiasts.
I found no problem in sourcing 60,000cS for the SME arm damper and 1 million cS for the arm drop. 1 million cS is very difficult to handle - it hardly flows at all!
Here you go - every viscosity you could ever need
https://www.modelsport.co.uk/accesso...es/9980/998025
I've just seen they do a 20 million cS one now!
Poise = Stokes for silicone greases because the density is 1. So the old Rocol Kilopoise range translates to units of 1000cS
Craig