Hello Partner, the current break you are using I think is the easiest to attain good results from. I find that using your current break from the position you have outlined, I generally can keep the cue ball in the center of the table after the break. (When aiming at the head ball no matter where from, you must attempt to hit as full as possible, or it will glance off the rack and go behind the rack) I do this by hitting the cue ball about a tip below center and about a half tip off center left if breaking from the left, and just the opposite if breaking from the right. Upon hitting the head ball with the cue ball it will deflect to the side rail and back out to the center of the table, and also remember that when breaking, do not hurry your break.
This is a problem that many people have, and they just do not understand why they do not not have good results. The number of warm-up strokes taken also should be very numerous, I normally take between 8 and 11 for break shots due to the force with which I hit the cue ball. Another thing that will improve your break is a more up right stance. Normally when shooting a shot my chin is almost touching the shaft, however, when I break, I am at a almost erect stance. This way I can put my upper body into the break for additional follow through and power.
Last of all remember when breaking and only when breaking it matters not which ball you look at last. Normally when going through your warm-strokes you glance back and forth between the cue ball and the object ball. But you must be focused on the object ball when contact with the cue ball is made. This is not the case with the break shot however, in fact I would recommend looking at the cue ball upon contact. Again the force used and the follow through necessary for a good break, along with the importance of keeping the cue ball under control throughout this process, I like to focus on the point where I strike the cue ball.
The thing I have found when breaking near the side rail into the second ball, is that many times you will get so much action that a ball will rebound into the cue ball and change it's final position. When using this break I hit the cue ball a little more center than the break above, but still slightly left of center when breaking from the left. When I hit the second ball I like to hit as close to the head ball as possible, and I use a draw stroke so that it will rebound off the rail and head toward the center of the table between the side pockets.
By the way, if you continue to come up empty on your breaks move the position of the cue ball a little right or left from your normal breaking point, or move to the other side of the table.
Hope this helps, and have a great night!!!!!