OK, just took a long hot shower and I think the lightbulb finally came on.
So the jig is to hold the arrow at the proper angle so that if you ran a router or a drill press along the edge of the jig, it would make a 90-degree groove in the arrow that would taper up the shaft to nothing. Four such grooves would make the end of the arrow look like an X or a cross. Two would make it look like a pie with the two opposite quarters missing. The former would be a "four point" footed arrow, and the latter would be "two point" right?
Then if you were making a two point, you'd do the same on the foot blank, and also cut a slot down the middle. Is that right? For a four.... you'd have to center drill it somehow at the same angle as the jig... and cut two perpendicular slots. That sounds much harder to do.
I assume you would cut the slots in the hardwood foot, rather than the cedar arrow?
Is it ok to foot with cedar to cedar? How about those oak dowels they sell at Home Depot?
I'm envisioning a jig like in the how-to, a 90-degree v groove router bit and the router dremel attachment. Does that sound reasonable? Not sure how I would cut the slot without a bandsaw though. Hmmm.