I don't use a jig, I freehand them. I split pen blanks, turn on center, drill and then free hand sand the slope. If I was making a jig, I would go with a jig similar to the jig that goose guts are made on. Making 1/2 at a time. I would also make it out of wood and use a router bit with a bearing to cut them. Routers are dangerous, I have all 10 fingers and never have made an emergency room trip because of my woodworking, I am too old to start now.
Marvin