If my swing is orbiting (pivoting) around my spine and the ball is positioned directly below this center point, the radius of the circle is the distance between the ball and the spine. This also defines the low point of the circle.
Can't read past here, ckniker. We have "issues" . . .
Namely, with the basic definitions of Swing Radius and Low Point.
Until we agree on these basics -- yours definitely are not those of TGM -- further conversation, questions, observations, etc. result only in more confusion.