You want the grain to run vertical but straight with the angle of the grip, and you also want the growth rings to run along the width of the grip, not the thickness, its kinda hard to describe what I'm talking about. Also when making the grips start with a piece that is thick enough to make both grips from, split that piece down the center to form the two grip halves then put the sides that were on the outside against the frame, that way the grain on both halves of your grip are almost identical.