I'm a 13 wide and never had an issue with any car doing it the traditional way plus it takes alot less effort. I applaud anyone for being different but your range of motion and sensitivity should be alot greater at the toes and top of the foots vs. the ball of your foot or closer to the center. Is your heel off the floor when you're doing this inverted heel-toe? Anythings possible but i seriously don't think it's nearly as effective as it could be.
http://videos.streetfire.net/video/S...NSXR_54506.htm