Larry, i don't know the exact math, but it looks like it's a system that uses 3 tips of English. 3 tips of English gives you a total of a 3 diamond spread the long way and 1.5 diamond spread the short way.
So if you look at the diagram, if you hit the ball parallel to the long rail with 3 tips hitting the 1st diamond, the cueball would end up at diamond 2 on the short rail that would not score. So this is making a 1 diamond adjustment to score (note that the cueball path is 1/2 diamond over before hitting the 1st diamond making a full diamond adjustment to score).
Not sure if it makes sense now or if I made it more confusing.
One thing is clear... This is the first post I've read from Cocobolo Cowboy in years - he is still an ass.
Interesting your English system/numbers are exactly 1/2 of what I use.
For me 3 tips across the short gives me 3 diamonds spread and along the long gives me 6 diamonds with a perfect setup.
I'm still struggling with how much spin is added or subtracted depending on the hit and angle of approach.
Clocking the Cue Ball is a big component in my game.
That said, on my best days, I struggle to reach 750.
Maybe I should calm down and accept your numbers. I can see the possibility that your numbers could possibly eliminate my struggle mentioned above.
My numbers come from simply spinning the ball into a rail at 90degs and figuring out where tip placement gives me 1, 2, 3, diamond spread across the short.