FWIW, I bought three *fat* *thick* picks made of bovine horn at a bluegrass festival. I love one of them because I like the sound it gets out of the strings. It also seems to get just slightly tacky as my fingers sweat, so it doesn't slide around or try to escape into the soundhole. Of the other two, the one that is polished gets too slippery. The other has the matte finish of my favorite, but has sort of curved over time, so it isn't easy to use any more. If you can find these picks, try them out; they seem to be fairly rare, as I don't find them often. Be aware, though, that they (like any natural object) vary widely from specimen to specimen. I do prefer a fat pick to a thin one though, and it took me about two years to figure that out. The thin ones are just too floppy.