The GP and SP spur hammers are an abomination of unnecessary sharp edges. I take a fine file and break a 45 degree bevel around the outside edges, then file the flat on top just enough to break the tops of the checkered surface. It makes a world of difference in the way they handle.
“Nine-tenths of tactics are certain, and taught in books: but the irrational tenth is like the kingfisher flashing across the pool, and that is the test of generals. It can only be ensured by instinct, sharpened by thought practicing the stroke so often that at the crisis it is as natural as a reflex.” ~ T. E. Lawrence