Timseal posted this link to fcsnooker.com. The whole article is about grip. It is probable that Figures Four and Five refer to the "V" alluded to by Lee Brett. Hope that helps.
the_grip.htm
I think that the usefulness is in the idea that it keeps your fingers aligned and tends to help you lock out side wrist movement. In addition, I think that most of us do not think about what it is that we aim with, we just swing the stick at the cue ball and let the brain take care of what is aiming the rear of the stick. A while ago I came to the conclusion that it is better to aim with something and to let my brain know what it was I wanted to aim with. To lock out the wrist I taught myself to aim with the area between my thumb and first finger. I did not know this was called the "V" grip and re-invented the wheel. The information on fcsnooker has helped to revise my thinking. With the "V" touching the stick (see figure Four). I have a better sensual feel for what is aiming the stick. I have just begun using it and I find that I immediately like the feel. There is more power available (it seems) and the sense of alignment is much better.
Your mileage may vary !!!