It’s not as simple as it sounds, because Bonaparte’s measurements—and thus Wallen’s too—were from the clitoris to the urethra (where urine exits the body), rather than from clitoris to vagina. (The urethra is dependably close to the clitoris and makes a more precise measuring point.) A clitoris is easy to find, but urethras are sometimes hidden inside the opening to the vagina, and often hard to see.
