There are lines and the memory of lines. If the wood is real smooth and the "checkering" looks like an inked line (happens on round pistol grips) it isn't going to keep the tool in the furrow. Go over every line to get the dirt out; don't go deep on one line at a time. I think doing it almost like layout lines for a two-bottomed tool is best. Do a couple lines in the middle. Do a couple other direction on the diamond. The fresh tracks are something for the mind to follow. Raking light and magnifying visors need help. Don't ride out at intersections; don't go uphill into crossing grain or emerging grain. Don't rock the tool, baby. Go slow. Curved rifflers (a triangular "float" type file) are said to be good for chasing; I haven't tried that. I don't have any 90 degree, only 60. Fine tool with lots of "points" or serrations seems to work best for me. I haven't done much of this so there are those better prepared to advise.
jack
