Steve,

Yes, they do have drill fixtures for the props, I know Cactus Aviation carries them(and probably many other dealers) and they have several bolt patterns on them for various engines. They also have a centering stub on one side that fits in the props center hole so they are centered. I strongly suggest you use one unless you have access to a rotary table or CNC mill or drill to do the job. Since all the bolts must fit through the front plate, the prop,the spinner and finally screw into the hub alignment and straight holes are imparitive and yes I do think you should use a drill press with the drill fixture and make sure the drill press table is square to the spindle front to back and side to side before drilling. Check your manual but I think most of the engine manufactures recommend the prop be aligned with the piston stroke and this is easy to do by rotating the drill fixture until the pattern lines up accordingly.
Hope this helps ,
Jim