And, while Rich Chang's guide above seems widely considered THE 1/12 guide (I've had a laminated copy in my race kit for several years now) here's another one I picked up somewhere. It comes at the "challenge" from the aspect of "the car is doing this, what should I do" rather than Rich's "if you change this the car should...".

See what works for you. I can't attest to the accuracy of info in this second sheet but a quick scan says it makes sense what I looked at.

Scottrik