Tuning Your Timing Tables - OpenTuner Notebook
someone will say 16* and the smallest pulley you can get away with. Most torque that way.
Someone will say 18* and the smallest pulley you can get away with. Better balance of torque, horsepower, and SAFETY in the case of knock.
And the link i sent you says 20-21. Most power, smallest safety net.
How agressive do you want your tune to be?