The purpose of a cut break is to create an angle that does not exist, because you are forced to break the balls from a position closer to the center of the table.
IF you break from the side rail there is no need to do a cut break. At the US open 9 ball players are forced to break from the box (area confined within the first and last diamond on the short rail) because of this the cut break is used almost exclusively by most players.
This is something that you need to experiment with, as the amount of the one ball you need to hit varies depending on lots of conditions including how close to the center of the table your cueball is.
As far as power, I would suggest only enough to make a ball, and not too much so you start to lose the cueball. You will NEED to inspect every rack carefully to make sure all of the balls are frozen to each other. Multiple gaps in the rack will guarantee this will not work.
Try first from the first diamond (either left or right, and start with a quarter hit on the oneball, and keep adjusting the amount you hit the one ball with depending on what happens to the rack when you break it. Remember since you are starting closer to the center of the table you are creating the angle on the oneball by changing how much of it you hit. If you start adjusting closer to the center of the table then you will need to hit less of the one ball
The biggest problem with the cutbreak is that it is very easy to lose control of the cueball.
The year that SVB won the open, he had IMO the best cutbreak I had seen in the tourny. He would break from the right side, with low left english on the cue. the cueball would travel 3 rails (Long, short, long) towards the place he broke from and the oneball whould head up table too. He usually made a ball, and was playing position on the one ball. It was a sight to see.
