I've been reading on the intertubes all about bras and fitting. Interesting stuff. I read that most bras are designed on the assumption that you are at least 5'4" so short people often have problems with straps being too long, with sides digging into the armpits, and underwire coming up too high in both the front and sides. Tall people have their issues as well.

Also, sizing becomes less accurate the larger your cup size (over a D) so the rules of thumb, like add a cup size for each inch, are not reliable. None of the sizing methods take into account volume. size and spacing accurately.

There isn't standardization between manufacturers (the rules of thumb of one cup up per inch, and under breast measurement plus 4 or 5 inches are not manufacturing standards) so you could wear different sizes depending on the manufacturer. Or depending on how much stretch is in the fabric.

Basically, you are left with trial and error or the rare fitter who really knows the marketplace.

Based on what I read and prior experience I think I will not bother to try underwire. I have tracked down a few softcup bras to try in my likely size.