I use shock oil (20 .. 40wt) / Losi hydra drive fluid / Corally damper tube silicone fluid. That's from thinnest to thickest. The advantage is that they're all more or less the same. I.e. they're all silicone fluids.
On another topic: what type of traction compound do you prefer? I'm curious about Paragron FX2. It's not commonly used in Europe, because it's not odourless :-s But I suspect it's *the* additive for carpet racing.
We mainly use Corally jack the Gripper, or CS yellow. jack the Gripper works Ok in all conditions, but the CS yellow seems a little more aggressive. there's also CS Blue, which is 'medium'. That helps when you're having traction roll problems, or you need a mild compound for the front, to reduce oversteer. The LRP product is the same as Jack the Gripper.