I agree Harry. Just use a center finding head to mark a line through center of your dowel and then mark the angles you want on the end plate of the jig starting from a point equal to the radius of the dowel. Really simple. Not sure why Bob would be worried about his fingers. There is a substantial piece of wood between the bit and your hand. Besides, it would be easy to make a handheld hold down. Also, not everybody has a Craftsman Router Crafter. However, everybody has scrap in their shop.Yet another cute idea Derek, the sort that makes one say "now why didn't I think of that".
I can visualise adding a simple indexing system to make multiple flutes on round stock.