Not "beside the point"
PJ, I understand your perspective because it used to be mine. Since then I have become highly aware that I created scenarios that didn’t match the facts. Let me explain using some research done by Dr. Dave.
From David G. Alciatore, PhD (“Dr. Dave”) ILLUSTRATED PRINCIPLES “Throw – Part VII: CIT/SIT combo”
https://billiards.colostate.edu/bd_articles/2007/feb07.pdf. Diagram 4
To put this in context, the idea is that every cut shot has some inherent amount of throw. Maximum throw occurs at about 30-35°, roughly a half ball shot, when slow stun is used. If however the ball has vertical rotation, follow or draw, and is shot with medium pace, the throw using
inside side is consistent. Regardless of angle, medium paced, draw or follow show a consistent throw deviation was found across the cut angles tested. There was 1° of throw consistent across the entire range tested. A rolling ball is a rolling ball when it contacts the object ball and is treated as follow. The only other state is a sliding ball, stun. When a slow stun shot with maximum inside english is applied the throw amount is slightly higher resulting in 3-4° of throw across that same range of angles. A center soft stun shot has throw effects varying from near zero to as high as 5°. The point is that inside side offers the shooter a consistent single adjustment across all cut angles tested.
Another graph
https://billiards.colostate.edu/bd_articles/2006/dec06.pdf , looked at the effect of degrees of english from small to maximum at varying speeds. A straight shot was tested to check speed vs throw dynamics. One conclusion stood out when considering a small amount of english. "SIT is independent of speed (i.e., the throw is the same at all speeds) for small amounts of English."
Logic tells us that the small amount of english dynamic, especially inside english, should apply across all angles consistently, regardless of speed, even at cut angles. In fact, one of the other graphs
https://billiards.colostate.edu/bd_articles/2007/sept07.pdf compares squirt dynamics for different speeds at different cue offsets. The smallest offset tested was .21". That amounts to 5.3mm of side. CJ defined his amount of inside as ⅛ tip. An eighth of a 12 mm tip is 1.5mm. The three offsets tested were .15" apart. That is about 3.8mm. Coincidentally the ⅛ tip CJ used just happens to be that much less than the smallest tested. While each of the tested offsets resulted in roughly a single degree less deflection as offset decreased, the trend is further confirmation that "SIT is independent of speed (i.e., the throw is the same at all speeds) for small amounts of English."
When CJ followed his process of shifting the butt then the tip slightly, he guaranteed a very small amount of inside. The sharpness of the angle to the inside forced him to temper the inside move on long shots. That in fact created a different offset. The research led to refinements to his system that address its problems and led to new understandings of determining true offsets. Consistent offset combined with the science of inside side allow players to significantly reduce the effects of throw. Complexity around adjusting for angle, speed and offset deflection all collapse into a single treatment for the majority of shots.
There is more, but the idea that all this is "beside the point" creates an avalanche of cognitive dissonance. I’m just sharing some of the things learned going down this path that changed my perspective. It’s rare that I now need to calculate adjustments for throw.
Outside side can be applied in a similar manner but the existing testing doesn’t give good reference results for such a small amount of side. That said, the difference between SIT and CIT is emerging as significant when small amounts of side are applied. My ideas around that are undergoing the same issue "that I created scenarios that don’t match the facts." But that is a topic for another day.
