Spidey, what you're attempting to do is to figure out the mathematical formula to calculate the exact pivot distance by working backwards from the the ghost ball aim line to the pre-pivot aim line (as determined by the pivot system in question). If the system is exact to begin with, then this formula should already be an intrinsic part of the system itself.The pivot def matters. The larger the pivot, the more it matters in order to hit the correct vector through the core (correct "center").
The pivot must always be executed from the tip-back, not the bridge-forward. This is figured from the edge of the shot circle (OB edge of circle, bridge at center--- you must pivot along that arc, which many times forces an effective pivot point behind the bridge).
Then you have perspective adjustments--- the OB gradually getting smaller than the CB with greater distance. When the OB/CB are close, your eyes must move MORE than when the OB/CB are far away (on the same alignment).
None of the above is every really though-out well in these threads.
I believe with a laser pointer, I can show a tolerance that's VERY small with no adjustment (one movement to the final position). This system is very math-based.
The guy who I had helping me got busy with other things. If guys like Dr. Dave / PJ really wanted to know the math--- we'd figure it out together. I have diagrams showing the pivot point offsets in 2D, but I believe they calibrate as the OB size decreases--- that's where I left off.
When I say "I believe it's exact" -- that's based on the info I have and the amount of adjustment needed when I play. I'll continue to say that because I'm confident that with the proper math-help, it'll be proven out in time. I'd rather be unpopular and right (for now) than in the "cool aiming police" group and flat wrong.
In other words, you're not trying to prove the exactness of the pivot point system. Rather, you're attempting to make an imperfect system (the pivot point system) perfect (ghost ball) by introducing an impractical fudge factor formula (pivot point calculation based on CB-OB distance and other things) into the system in question.