Read the whole topic.
First of all: There is no way without programs that a shot will hit by 100%. No matter what technique you use for aiming, there's always a chance to miss.
Now, let's use Cue's definition of notching:
"1 pixel tap is a notch if it is counted in sequence from the vertical position as part of the notching system."
Lets call the vertical position "position 0".
Example: You have to get the angle at position 7 to do a perfect hit.
Solution 1, first shot: You just start at position 0 and do 7 taps/notches. VoilĂ , you're at position 7 now. This is what Komo calls notching and lame.
Solution 2, first shot: You try to guess where position 7 is. Depending on your experience you're more or less good with this method.
Solution 3, first shot: You try to guess where position 7 is and you remember your aim at this shot with some method. (texture, thumb, etc.)
Solution 1, second shot: You just start at position 0 again and do 7 taps/notches.
Solution 2, second shot: You try to guess where position 7 is again. If you were far away, your shot will probably be better now. If you were at position 6 or 8 at your previous shot, then your second shot will be as random as your first shot, because you just can't know what adjustment you need to do, because you don't know your angle from your first shot well enough.
Solution 3, second shot: If you were far away with your first shot, then you can just make some rough adjustment, like in Solution 2. But if you were at position 6, you just have to get back at position 6 and move the aim by 1 tap/notch.
At Solution 1 and 2, you will always do the same thing. In Solution 3 you should get better results in every shot if your "aim remembering method" is exact.
It is mathematically easy to proof that the more angle you need, the easier is solution 3 ("thumb-aiming") compared to solution 1 ("notching").
It only depends on the error ratio of your methods to say which method is generally easier.
You are in fact counting. Instead of counting from vertical you are counting from your last shot. You know how man pixel movements you were off by and adjust by counting that many pixels from your last shot that you have marked with you thumb.
But you call it what you want.
I will call it notching from your last shot.
Johnny is absolutely right with that. The difference between notching and the "thumb-method" is simply in how you get the aim that you previously had.
Dunno if my opinion is clear at all, so her it is lol xD
I think any method of aiming is fine as long as its not tool-assisted (and by tool I mean any kind of software-technical help). You just need to try that your shots explode on impact and you should vary your shots.
Addition after reading Komo's last post: If anyone else would learn notching like you in 1 week, we would have 2 unbeatable players, and a match between them is interesting again.
Or you think that you're by far the best in the worl in learning how to notch?