Too many bowlers think they will get better lift with tight fingers. The problem arises when the finger joints don't make it all the way in, which has the effect of changing the span of the fit. Thumbhole size is adjustable using bowling tape. When the hole is loose, put tape in to take up extra room to avoid squeezing. The human thumb fluctuates for different reasons including temperature, humidity, amount if use, and fluid intake. Failing to use tape is to suggest that thumb does not ever change and this simply is not so. Using enough tape is often the difference is being able to maintain proper grip pressure, especially in the downswing toward release, from shot to shot. A loose thumbhole creates squeezing.

    The span is the distance the each finger hole drilled from the thumbhole. It is the length from the base of your thumb to the joints in each finger. To check your span, put your thumb in all the way to the base and place your fingers across the finger holes, without putting them in. Your ceases should lay about half way in between either edge of each finger hole. If they do not make it that far, and the crease is closer to the edge closest to the thumb, it may be too long of a span. If  the creases are past the holes, it may be too short of a span. This is a raw check to see if you are close.

    The pitches are the angles at which the holes are drilled. Drilling the hole toward the direct centre of the ball is zero pitch. Drilling the holes at an angle toward the centre of the grip is forward pitch. Reverse pitch is drilling the hole at an angle away from the centre of grip. Finger pitches are largely determines by flexibility. The holes need to be drilled at angles that fit the amount of flexibility in the fingertips. Over time, bowlers tend to lose flexibility in the finger joints and need more reverse pitch in the finger holes.

    The thumb pitch is another matter and this is related to the hand span. Generally, the bigger the hand, the more reverse pitch is necessary to get the thumb out clean. The shorter the hand, the more that forward pitch is necessary for a secure grip. Keep in mind this is not an exact science, as an expert on ball fit will take into account flexibility and the length of the thumb.