I have to say first that Efren uses the pivot system, that in itself should tell you something. When he explained it to me it was after his shooting a dead straight shot with 2 tips of right and 2 tips of follow, in other words a dramaticly two o'clock shot. He did it by aiming straight to center on the OB and pivoting for the spin leaving his bridge in the exact same position as he stroked through the ball.
I didn't believe that that was what he was doing or that it would work for every shot. In fact I didn't even try it to see if it would work until three years later when Chip Klein was talking about it down in San Diego so I thought I would try it. Sure enough it works.
The 1/4 ball and what not is just another way to find the aim point for the proper contact points. If you think about the curve of the CB and the OB as they are coming together from different angles you;ll realize that there is a specific amount of off aim depending on the angle of the shot. Once you understand that you still have to be able to accurately determine the angle of the cut to be able to find the right aim point.
I personally feel the ghost ball technique is the easiest or I just use one of the techniques to get on aim and then just trust my feel for each shot after I get on using an aiming technique.
That works fine but you still have to know the technique for when you get off and can't figure out how to fix it.
Once you have the proper aimpoint it's just a matter of pivoting for the right English, and stroking straight through the shot at the right speed. Easy right? Just run out and you'll be good.