I just honestly can't understand how folks have so much trouble with aiming. I'm with her.
You're aiming point is exactly 1 ball width from the center of the OB, in a straight line opposite the direction to where the ball will be pocketed with the center of the CB. You should become very good at estimating this quite quickly if you realize this. Obviously you have to adjust for conditions, CIT and spin and speed. This can be learned at the practice table. Stay down and watch on every shot to learn, and
visualize the OB pocketing before you ever pull the trigger. You know how balls roll and how they behave at some point. Visualize it pocketing, if it looks right, it is right.
I know it works for some but all this talk of fractions, centers, edges, etc. is honestly not needed for me at least. Get a good look at the ball and let your subconscious pool computer figure it out. If it looks right it is right. Your body/mind knows. If it feels wrong, it is wrong, listen to that trustworthy feeling you have before a shot. I mean, if it calms a player to imagine fractions or even a blue rhinoceros on the PSR, then whatever works I guess.
It might be different trying to teach beginners but my goodness does a pool player really have to think fractions to see how to make a ball? It seems preposterous to me. I don't mean that disrespectfully. I understand the concept but overlaps and fractions just don't compute for me personally. It seems like extra homework when you already see the shot. Take the time to visualize the ball being made before you hit the CB. This step takes focus but should not be skipped. Practice focus, because it's a major part of playing at a high level.
I understand there are different ways to explain aiming, different students/players think differently, but in the end if the results are the same, the aim was the same no matter what you had to think about or what system to achieve it.
EDIT: I know there are anomalies, but watch the straightest shooting pros. Watch their practice strokes. Watch them feather the stick. If you really dissect the footage, you should even be able to tell their breath work before the final stroke. They are focusing. They are visualizing the ball going into the pocket. If it looks wrong, they get back up, look a bit, throw some chalk on to clear the old "bad feeling" (it looked wrong) and replace it with the proper perspective and visualization. You can definitely tell what the straight shooters are doing. Hell, in HD you might even pick up their pulse in the stick on a touchy situation. Shoot between the heartbeats if you have to.
In the past folks hid all this stuff under the guise of hustling and not to let any secrets out. It's dead simple. If it looks wrong, it is wrong. Visualize the shot with the knowledge you gained at the practice table and execute it. Again, they aren't poking the ball and it's all very deliberate, even down to the breathing. They are consistent because they practice making every shot the same.