in a nutshell, you have palms down(German), palms facing(French) and 3/4 (American compromise!). Of course the thumb in all three varies with the palm direction.
I just had my first lesson, and we are using the French Grip to show me how the sticks can do most of the work through gravity and rebound, reducing the effort it takes to play. I have no idea whether we will stick with this grip or not, I just know the exercises are working!
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