thanks SA for these pictures.
the release point for a real serve.... I meant that's the point when the racket is at full extension, as shown in your Sampras picture.
regarding pronation - the racket did rotate on it's long axis, but only did 2-3 revolutions in the air.... does that sound right? the head over butt tumble was much faster though, not sure, maybe 12 revolutions in the air.
does that sound right?