The leading hand's position is generally deamed the "strength" indicator. Top is strong, to the side is weak.

I personnaly advocate the trailing hand's position to be on top...this pre-cups the right wrist, and allows for an anti-swat move (horizontal hinging of the wrists is bad, vertical hinging is good), so anything you can do to reduce the ability to hinge the wrists on the horz, I like).

Can you have the trailing hand on the side of the grip? Sure. Just be careful to keep from trying to use it for power, because if you try, you might get 1 good one with some nice power, but 8 others will end up 20-30 yards offline.

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I'm a golfaholic, no question about that. Counseling wouldn't help me. They'd have to put me in prison, and then I'd talk the warden into building a hole or two and teach him how to play. ~Lee Trevino