I shot the pathfinder tipped rockets this past year and also was not totally satisfied with the sharpness of the head. He is how I went about getting the pathfinder tips scary sharp.

Take a piece of 600 grit wet dry sandpaper and wrap it around a fat magic marker. Take the two ends on the underside of the marker and pinch them in a bench vice. This will pull the paper taught around the marker.

Now push the pathfinder points forward on the paper. The roundness of the marker conforms to the concave shape of the heads and gets the edges the whole way along. Once you are done with all 3 sides, the pathfinder will essentially be sharp enough to cut yourself with.