grober
MB Master
I would encourage the 10 to 2 position rather than the quarter to three since ergonomically this would dictate a slight bent arms position which conveys a better mechanical advantage to exert a turning force on the wheel. I reckon this is the origin of the 10 to 2 recommended position dating from a pre power steering era. With regard to the "thumbs position" if you ever go on an off road course one of the first things they teach you is not to wrap your thumbs round the wheel rim. I am surprised Mercedes don't mention this in their ML owners handbook- maybe they do.