Some people may also find the process easier than others due to being able to bend the thumb back at 90 degrees
Nick, you should be in a circus!
My thumbs don't even bend back 1 degree, but having said that I have never had a problem with CMH (It got the thumbs up from Michael Ammar), so I guess bendy opposable digits doesn't really come into it. I think this one is just down to ptactice, but if there was ever something worth while practicing, this one is it...