I would answer it this way. The precise nature of movement is entirely separate from conscious intention. Conscious intention is too slow. The practice of precise movement allows us to move at a pre-conscious level.
I hope that our paths cross on one of my trips to Japan. I would enjoy training with you followed by some good Japanese beer or sake....
There is no difference between Ushiro Sensei's sword work and empty-hand work. The best way to describe my experience is that a bunch of us put our hands on his body. As he made a movement to prepare to draw an imaginary sword, all of us felt him physically expand. He literally entered in a 360 degree manner. He was everywhere yet nowhere discernible. When his sword is drawn in this manner, you do not perceive it in the same time frame that it is drawn. His irimi is ahead of our awareness and connected to us at the same time.
With Imaizumi Sensei as a silent force and Ushiro Sensei as a more vocal force, if I cannot begin to comprehend and learn some of this stuff with such quality of teachers, I am beyond hapless and hopeless (which is how I feel more often than not)