I still believe the best aiming system is not picking a spot on the object ball or the even ghost ball. To me this is not the complete shot. The whole shot is what I believe needs to be the aiming system. You are first taught to hit balls into the pocket without the cue ball, that is the visual - that is the complete shot, the ball to the pocket.
Picture this; An arrow through the ball so that the end of the arrow is flush with the back of the object ball, the tip of the arrow is pointing and is touching the part of the pocket you are playing. When you align the shot you are seeing the shot in entirety as a three dimensional one. You are hitting into a path, not a spot. So the aiming method is a path, not a spot. You now create a complete visual of every COMPLETE shot. If you are off a little, it is so much easier to adjust.
What it helps with;
1.If balls are a little sticky because of humidity, you are playing high and low english shots,... the path changes slightly and it becomes easier to build in a mental adjustment that stays with you.
2. Difficult shots are now incredibly easier (long cut shots), you just see them
3. There are fewer parts to the shot to worry about. Finding a spot and adding a ghost ball is just too limited and adding to many parts. Keep it visual, simple and complete.
4. When another ball is taking up part of the pocket and you have to be more precise, you can know see the path clearer.
When I hit a golf ball I do not look for a spot on the back of the ball, I see the complete shot. That is the path of the golf ball and where I plan to place it onto the fairway. Same with hitting a baseball, making a hoop,,, and everything else.
I have shown a few who now make more shots than ever. My 9 year old son who started playing 5 months ago is making great shots. Someone tried to tell him about the ghost ball when he first started playing, I stopped him and told him NEVER to look for a spot to shoot at and never create a ghost ball - always see the entire shot. He plays about 2 times a week for about 5 months now and now beats many of the teenagers that come into the pool room on Friday nights to play. He makes great cuts. Now, he just sees the shot and where he wants the cue ball. Its all paths. The shot does not end at the ghost ball or the spot, that is dead end. The shot ends in the pocket. Fewer parts and very clear.
In my opinion this is the best method. This creates the complete visual.