I think a lot of us use 1T PPO (per pound of oil). I use that amount but I use whole ground oat flour instead of grinding it myself. Using less or more coarse oatmeal might change how much you want to use.
Dave, I just want to clarify since you typed a lowercase t (possibly for teaspoon), our T is referring to a full tablespoon =) If you aren't sure what you'll like more, you might try a 2 lb batch, split in half at trace and add 1T to one, 1t to the other. After a week, it should be cured enough to test both on your hands to see which "scrubby" you like more.