When pro bowlers bowl, do they look at the pins or their target spot on the lane when delivering the ball?
If you have looked at and analyed the shot and angle before getting down, have lined up properly, and have good, repeatable fundamentals and a straight stroke, it shouldn't matter much what you look at last.
Once I get down and assess the shot after all the above, I assume my angle, stance, etc. are already correct and the only thing left to do is hit the target with whatever speed and/or spin is necessary to control the cue ball after the shot is executed.
Since the tip is the only part of the cue that touches the cue ball, I consider the cue ball to be my "target".
I am sure I occasionally switch my style of focusing, but it probably depends upon the complexity of the shot, or whether I can get my body in the correct positioning due to the table layout.
