There are a scad of good carvers for a particular shape of pipe. Select a carver you like and ask about the shape you want and if he feels confident he can deliver it. If you like the carvers responses you can sign a deal with him or just move on to another carver on your list. Silly as it sounds if you're any kind of stickler for detail let the carver know. You can say "billiard" to these guys and what they hear is "your take on a billiard". And you do not want that.