Justin, why wouldn't you use the actual PSA of a drilled symmetrical ball which is always in the thumb?If you have a DeTerminator to locate the PSA, that is ideal. The gradient line location procedures outlined here are for those without the hardware. Since we know the PSA of a drilled ball ends up near to the thumb hole a majority of the time these procedures are accurate.
The PSA movement based on hole placement is the reason for 2 different methods. Keeping the PSA near to the thumb hole in the "Parallel" method increases the drilled differential and ratio while retaining a largeer after-drilling drill angle. Moving the PSA away from the thumb using the "Projected PSA" method results in a PSA location closer to the balance hole, reducing the after-drilling drill angle creating the earlier reaction.
Are you saying that a TR2 drilled with a 70* drill angle will roll and perform the same as a TR2 drilled with a 30* drill angle assuming the pin and val angles are the same and that you use the weight hole to change reaction alone?Yes. With no hole placed, the two will react so similarly there will be no noticeable difference in reaction.
I have found that all four components of Mo's dual angle technique, (drill angle, pin distance, val angle, and weight hole placement) are equally important in obtaining a desired reaction. I know for me a ball with a 30* drill angle is going to start rolling at my toes, while a 75* drill angle is going to skid till it hits dry boards. I use the pin distance to manage the friction and the val angle to determine how quickly I want the ball to come off the breakpoint. I'll then use a weight hole to fine tune what I have created. If I definitely know I want a P3 I choose a ball with a top weight that will allow me to do that.In an Asymmetrical ball the drilling angle is significant. In a Symmetrical ball, the drilling angle strictly sets up imbalance to facilitate the hole placement.
A combination of small drill angle and the "Projected PSA" method of gradient line will create an earlier reaction for speed dominant bowlers or low friction environments.