Hand size is measured two ways and both count. Length runs from the wrist crease to the tip of the middle finger. Width is taken across the knuckles with the fingers held together. From roughly 19 cm of length upward you are in large territory, and that is the point where a standard 115 to 120 mm shell stops filling the palm.

The answer is not simply a bigger object. What a large hand needs is body length in the 125 to 132 mm band, paired with a rear hump tall enough to fill the hollow of the palm and set far enough back to sit underneath it. A long but flat shell still leaves the fingers curled and the wrist carrying the weight.