Thanks for the input, Steelers Fan--much appreciated!! I totally get what you're saying. I guess I'm just trying to find some quantitative measurement, even if imperfect (and the clothes sizes are way better for me than the scale). It helps me to bring something more of an abstract idea into a more tangible goal.
I hear ya about being busty. I'm 40 D/DD myself, though personally, I think bras have changed in the last 10 years or so, that they're running smaller than they used to. What used to be a C is now a D (kind of the opposite of clothes sizes). I expect to lose a cup size, and I'll be more than happy with that. But many will probably think my boobs have gotten bigger because the rest of me proportionally will have gotten smaller --- one of those visual illusions that work in my favor.