Cup size is the proper way to measure. Chest measurement basically gives aindication of how large the person is around the chest. They could be a 40 with B cup meaning that they are are heavy with small ones.
We have a wood carving very much like that of my mother in law. We got it when she died. It was done in Germany by some artist she knew when she was young.
She actually had in her living room in her home in Virginia and thought nothing of telling people it was her. Ours is a little more explicit though if you know what I mean.
You can't show it to children. My mother in law was a real piece of work even in her 80's.