This f-hole is on a Brothers Amati cello dated around 1615. It’s one of the most beautiful I’ve seen and is perfect in execution. I’ve used it on a cello, and reduced it to fit on a violin, and a violino piccolo. In each case, when it’s the right size, it superimposes over the original model’s 4/4 and piccolo f-holes precisely, with no changes. That’s something would not have thought would happen; usually parts between violin family instruments don’t transfer well with a simple percentage change.