There are lots of aiming systems that are just plain wrong. If the student actually follows them they may work but only as long as the student gives enough control to his subconscious to let it make the ball.... Is it worth the $54 to try to learn his system from him? Of course it is. Why wouldn’t it be? You haven’t actually tried it yet.
I think the real question is what is the best way for judochoke to learn how to aim. I doubt that it is 90/90.