When looking at layouts, you can look at them 2 ways....one in regards to the gripping holes or one without. When you lay out a ball, the gripping holes have to be taken into consideration due to the track or flare rings tracking over the gripping holes, either the finger holes or thumb hole. Layouts are used to manage track flare as far as reaction and not hitting holes.
Pin down can be described or looked at 2 ways.....one in regards to the gripping holes or in relationship to the vertical axis coordinate.
If you have a bowler who is 5 1/2" over laterally....but is 1/2" up vertically, then a pin down would be below a line that would be drawn from the PAP to the NAP through the center of the grip. The negative axis point is 13 1/2" from the positive axis point through the center of the grip.
We think pin down in regards to the gripping holes due to where the gripping holes are in relationship to the core and mass removed. It is more relative for those that track high in catching either the thumb hole or middle finger.
To figure out if the track will catch the gripping holes, draw a line from the PAP through the pin to where it will dissect the track. This should give you a relative point of reference as far as where the bow tie will be and where the track will or will not catch the gripping holes.
If you drill a pin below the gripping holes and the the track catches the middle finger, a weight hole down the VAL should raise the bow tie thus moving the track away from the grip as well as the middle finger.
This also can be the case if the track is flaring over the edge of the thumb hole in the front part of the lane. A weight hole down as well as a larger sized weight hole can increase flare helping the ball to migrate or flare quicker moving it off the thumb hole.
Hope this explains as well as answers your questions....
The views and opinions expressed by myself are solely those of mine and NO one else, nor are they affiliated with anyone else.