Zero for me. I used to look into them but don't anymore. My pool teacher shows me I can hit the size of a piece of chalk when I aim at it. Most of us don't even aim at the different sections of the pocket as he does. Every lesson, he shows me what a difference of the cue ball angle depending on how we hit the pocket thick or thin or in the middle. Too much information for most pool players though as I've found out posting that on AZB. You've got to see it before anyone argues about it.
What do you mean "...hit the size of a piece of chalk.."? You do mean with the object ball, right? If you're talking about the cueball, that's laughably inaccurate! Even if it's an object ball, distance would have to be mentioned as well, both between the cueball and object ball and the object ball and the target as well. I'd venture to say that you'd not make a lot of combinations (other than through luck) with accuracy of that calibre.
I know no one will do this, but here is a test that you can do to see how accurate you really are (modelled on an Efren Reyes shot). Start with the cueball behind the head string and try to clip a ball at the other end of the table, close to the rail as thinly as possible, so that it only moves a couple of inches,while the cueball comes all the way back down. Once that becomes easy, try hitting it even thinner...
If you practise this shot for a while, you'll learn why most people that shill aiming systems, as well as those who critique them are full of bs.
Here are the cliff notes for those that are "too busy" to try:
1. No aiming system will show you exact and repeatable steps on how to do this shot, cold and straight out of your chair. If you are talking about a snooker table or similar and you are diagonal to the nap, it's pretty much all subconscious adjustments.
2. This shot does come up
3. You'll notice that with practise you'll get better and better to the point that your success rate will increase hugely (if you are a competent player). This proves that the stroke is plenty good enough, once you have the alignment dialed in. That is the whole key point to understand. It also proves that aiming is almost secondary on this shot. You'll "feel" it more than you see it. The trick is to get the body in the position where the stroke can do it's job. This also explains why it is so difficult to do it perfectly on the first try. You are more or less "walking" the shots in, like you would shooting an smg from the hip.
4. "With of chalk" is laughable. More like a mm, maybe even less...
5. Neither stroke in itself, nor aiming in itself causes you to fail this shot. It's rather the alignment that is the critical factor, in this as in other pool shots.
