something I noticed this weekend regarding running out of right arm. Make sure you are not sliding the hips on the backswing. I actually keep the right side of my foot slightly off the ground to make sure I turn and don't slide. If you slide to the right, you've effectively taken yourself further from the ball and it can be difficult to get back. Just a thought..
The hip action is slide-turn in the backstroke.... it is very crutial that you do this....
Just maintain the stationary head and keep the balance inside the feet as you do this....