gonZo - good point, I didn't think of that... Guess I have to say that the shape comparison is not valid here. But Nancy (we think) is natural, while we know that Candy was augmented.
If you buy the idea that the general breast proportions - length, width, projection - are near equivalent, then you might suppose that the overall volume is similar. That's if both women are about the same height and overall size.
That's a lot of If's. I might not be saying anything here. Take from this what you will...
-D'Artagnian