I see a slight angle change now that I look more closely - but it looks like the angles get steeper, not wider, as the OB moves toward the head string..?
I don't think it's the same as you move the starting point down the end rail (toward the bottom of your pic).
i am confusedLol....as usual, we are not looking or referencing the same thing.
But it really doesn't matter. I was using a mathematical ratio of 0.67, meaning that when an ob is froze to the rail X amount of diamonds from the end rail where the target pocket is for the bank shot, the cb to ob offset line is X * 0.67 to make it a halfball shot. This works for all frozen rail banks after about the 2nd diamond up. I know that sounds confusing. I did the numbers while at work, then went home to test it out, and found it very accurate.
Of course speed is a variable. For instance, the actual line for a halfball hit to bank an ob 5 diamonds deeper down table would be 5 * 0.67, which is 3.35, or basically 3 and 1/3 diamonds. So starting on the rail straight across from the ob, and exactly at the same diamond distance, count 3 and 1/3 diamonds up the table toward the nearest corner pocket, actual 1/3 passed that pocket. Sight a line from here to the ob and that's the halfball line. It's really directly over center pocket, but it's not so speed sensitive if you go a little wider, which is why I showed it wider than that in my quick illustration.
So you're right, there is a very workable system system there, but it doesn't look as accurate on paper. But look at that ol halfball shot where the ob is froze one diamond up from the corner, and the cb is lined straight up with it so that the centerline between the balls is parallel to the end rail. That shot doesn't look right, but it works. Or the shot where the ob is froze to the cushion about an inch or so from the side pocket, on the head end of the table, and the cb is straight on with it (parallel to end rails). Hit that shot just a touch aiming just a touch off a full hit and you'll double kiss it diagonally into the corner pocket on the foot side of the table. That one doesn't look right either, but it works.
One such system is the 70% mirror system. Dr. Dave has a slightly different system.
Just curious...Lol....as usual, we are not looking or referencing the same thing.
But it really doesn't matter. I was using a mathematical ratio of 0.67, meaning that when an ob is froze to the rail X amount of diamonds from the end rail where the target pocket is for the bank shot, the cb to ob offset line is X * 0.67 to make it a halfball shot. This works for all frozen rail banks after about the 2nd diamond up. I know that sounds confusing. I did the numbers while at work, then went home to test it out, and found it very accurate.
Of course speed is a variable. For instance, the actual line for a halfball hit to bank an ob 5 diamonds deeper down table would be 5 * 0.67, which is 3.35, or basically 3 and 1/3 diamonds. So starting on the rail straight across from the ob, and exactly at the same diamond distance, count 3 and 1/3 diamonds up the table toward the nearest corner pocket, actual 1/3 passed that pocket. Sight a line from here to the ob and that's the halfball line. It's really directly over center pocket, but it's not so speed sensitive if you go a little wider, which is why I showed it wider than that in my quick illustration.
So you're right, there is a very workable system system there, but it doesn't look as accurate on paper. But look at that ol halfball shot where the ob is froze one diamond up from the corner, and the cb is lined straight up with it so that the centerline between the balls is parallel to the end rail. That shot doesn't look right, but it works. Or the shot where the ob is froze to the cushion about an inch or so from the side pocket, on the head end of the table, and the cb is straight on with it (parallel to end rails). Hit that shot just a touch aiming just a touch off a full hit and you'll double kiss it diagonally into the corner pocket on the foot side of the table. That one doesn't look right either, but it works.