You're both wrong. Any item can be used as an objective reference for the purpose of measurement or alignment.
If a person knows their shaft well enough they can use it to align to the shot and be very consistent once they figure out the parameters.
I find it funny that some people have this aversion to using more concrete methods of aiming. As if somehow this takes the romance of the game and makes it clinical and surgical. Slice the ball into portions, dissect that balll, etc...... maybe it's just me but it seems like some folks in this thread prefer to just guess when they aim and they are mad if other people don't want to be guessing all the time.
No, it's impossible. I guess you know the difference between 3/4 and 2/3. Or 75% and 66,6%. And you tell me that you can look at one or another ? At any distance ? And you can also tell me that the results are the same when the object ball's "size" changes as distance increases? You aim a bigger cue ball to a smaller object ball.
No way you are getting the same results.
It is a "feel" system. Not objective at all.