http://www.accuratepowder.com/data/357.html
AA#2 Improved is sorta like Bullseye or Clays. Find a .38 or .38+p load for the same bullet. Using a near max load for the .38 as a good start-middle load for .357. I do this as there is more case capacity for the .357, so you need to increase the powder bulk a bit. The pressure tolerance of a .357 is so much higher that this should create a decent load. I've used this procedure to create loads with Clays, Bullseye, and several other fast powders. BTW, use a small pistol primer. With the relatively light charge and bulk size of #2, you won't need a magnum primer.