Gord,
I was thinking of doing this myself. I continually hit off the heel with push/slices to the right. I saw my swing recently on video and it appears that although Im inside to outside (which is good, IM told) I straighten up on down swing, with my left arm extending too soon. I was advised to place golf ball outside of ball that I want to hit about 2-3" and then try to not to hit that outside ball. Is this the same drill as placing the cardboard box outside it. I seem to always hit the outside ball. Should you be clearing the ball and in your drill not touching the box?

Thanks.

Mike