15-20 grains of Goex FFFg powder for rabbits, and squirrels: 20-30 grains for larger game, like turkey or ground hog, or coyote. Use a RB, of course. You can try using #1 buckshot, which is .30" in diameter With a .015" patch) , or even 0 buckshot, which is .32" in diameter, With a .010" patch. If either of them work for you, you can buy buckshot cheaper than you can cast the balls yourself- now that lead prices are falling again. Accuracy is excellent with the Buckshot loads, and they are more than adequate for squirrels, or that rare shot at a turkey. Just remember that a .32 is normally a 25 yd. gun, with a 50 yard shot hat larger animals okay. The little balls lose velocity very quickly , and just don't have the weight to penetrate animals at longer ranges. The small ball will kill a coyote out to 100 yards, however, with a well placed head or neck shot.
The reason these small bore guns are so much fun is that you can practice your stalking skills on the game you hunt with it, and those skills will help you get closer to deer in season with a larger bore gun. Having said that, When, and where it was legal to use, the .32 has killed a lot of deer with shots through the ear at close ranges.