didn't read every post of this thread but centerball is dead easy to find: place another ball frozen to the first ball, and the point they are touching at is a very true center. This spot is tiny enough to eliminate any need of zooming into it.
P.S. what I just posted might be totally irrelevant but I just ran across the thread title and read only few previous posts like mentioned.
I thought "centerball" was the CORE. Therefore we can aim at centerball with any elevation of our cue stick.
The real referance point in the cue ball is the core. The outside surface is just a contact point. There is only one core and many contact points.
randyg