A semi-wadcutter round would be a good place to start for a HD round as they can be driven faster than hollow base wadcutters. You do get a little more velocity with a +P round, but the gain in velocity over standard rounds is not very much in a snub compared to longer barrels. And in a model 10 there is still not going to be much increase in recoil. They do flash and bang a little more though and that's kind of fun. I do use +P to keep around the house just in case.