Use a 19 to 21 tooth depending on track size.
What pistons are you running? 10x1.1 use anywhere from 25-30 wt oil. 8x1.3 use 30 to 35 wt oil. I never really had my car feeling dialed with stock pistons, so I'm not sure what works best if you run stock pistons.
I have bought both sets of pistons for my shocks, but I still run the stockers for now, what applications do you use for the specific pistons?
Right now I have the JR Mitch setup in my car, minus the option pistons as I didnt have them at the time, and for me its pretty good, some minor push in the front end on tight turns, but nothing I cant live with.
Thanks