Playing pro level pool is about natural talent more then knowing secrets about aiming systems. I have watched players go from young beginners to near pro level. I watched one guy from my city go from a level where he would never play me for cash to a level where he beat 4 well known pro's in a row in the US Open. He was not playing much more pool then me when he blew past me, he simply has a better eye and more natural talent for the game. In a city where he is in the top 5 for natural talent I am maybe in the top 50, and there is a big difference in actual natural talent between those two places.
The game is not rocket science, you have two round balls and there is this contact point on the object ball that will make that object ball go into the pocket. If you hit that cotact point the ball will go in, if you miss that contact point you will miss. Virtually all of the top players simply subconsiously aim the round cueball to hit that contact point on the round object ball because they have shot alot of pool and the information on what the proper aim "looks" like stuck for them. Some players can visualize the shot better by cueing at the contact point on the object ball and then getting into the shot after seeing that point, some don't have to do that. At the end of the day aiming is simply making the cueball hit that contact point. If you are trying to do 1/4 ball, trying to visualize an actual ghost ball in the place where the cueball needs to be to hit that contact point, ect... you are overcomplicating things and taking your mind off the place it needs to be, cueball placement and shape.
For the pros and top players the aim is a given, so they can focus on the other aspect of the game that really matters, the shape. If your aim sucks so that you need to focus on aiming systems, ghostballs, fractions of object balls, ect... you are screwed because the top players don't think about the aim, it is automatic, they are thinking about the shape off of an angle that will pot the object ball that came naturally and subconsiously to them.