Prepare the ground surface of the foot so that, in this neutral position, it is in a plane that is at a right angle with the imaginary plain that bisects the horse. This fairly simple procedure will provide the sound horse with a configuration that will allow it to perform to its maximum potential. With some practice this method becomes second nature and good things begin to happen. Feet come to the ground flat. Sound horses don't interfere anymore.
Feet stop having asymmetrical flares because they are loaded as evenly as possible.
You don't have to find a flat floor to work on or pretend to see things at the trot that your eyes are not quick enough to see. You can leave your client knowing that what you did was correct. Another benefit from this is that if you feel sure that you have put your horse in the proper configuration and you find that a foot does not come to the ground flat as the horse moves then you can be pretty sure that the horse is not sound. This theory of what balance is and of how to find it is an empirical statement that has arisen from my own observations of how horses move. Or, in other words, I cannot prove or defend the theory scientifically.