I wanted to say the same thing as M. Ted just did. I avoided it because I was afraid I might sound a bit too argumentative, but...

Although I believe economy of motion is a good idea, I think how far off the frets one comes will be arrived at naturally, and it may, as M.Ted said, be counter-productive as a matter of practice to worry about.

As evidence offered within this thread, may I point out that the fellow who suggested the concept, Bill D, said " I watched thru binoculars Doc Watson, Norman Blake, Tony Rice and Dan Crary playing together,,,but ONLY Doc kept his fingers to minimum height...I guess not being able to see forced him to not get too far from his next note! "

Maybe it's not stating the obvious. Norman Blake, Tony Rice, and Dan Crary are all at least as fast as Doc.