I just use diamond stones to sharpen them now, the grind is so much better. Take the paint off the steel by the edge, lay it on that bevel, and stroke it on the stones. I use the 6" smith stones, but wish I had the longer ones. I attach the head temporarily to a 8" piece of wood arrow for grip. Coarse stone until it shines, fine to a polish and it shaves, and WOW!!
The deer I shot with the 170 single bevel looked like I shot it with a 2" expandable the holes were so big, and the blood trail was easily 2 ft on either side of where the deer ran, starting right where I hit it, and all the way until it expired. When the deer jumped, I had to try and figure out where it was actually heading because there was so much blood. I hit high lung and exited mid lung.
I didn't ever see these kinds of blood trails until I started modifying the SB griz (pre new owner) and getting them like razors. I used to just use a file, but I see a dramatic difference. I can still shave with that head, except the back 1/4" on both blades.