I have an extraordinarily small hand ... But I have natural flexibility so ...the distance between my little finger and end of the thumb easily covers a 9th and I can just about reach a 10th.

That's small? I can't quite reach a 9th.

Higgeldy Piggeldy
...Sergei Rachmaninov
...wrote his concertos for
...handspans like wings.
Few realistically
...can pianistically
...digitalistically
...play the damned things.