I wish all manufacturers thought women were tiny! I am 5'4" and 120 pounds and small-boned, and my biggest problem through OW was BC's that were way too big and allowed the tank to migrate from side to side and destroy my trim.
I bought a small Libra, which was much more satisfactory, but still had a lot of degrees of freedom.
I am now diving a BP/W setup that is not the prescribed size for me, as it was bought for a much larger man, but it's more comfortable and FAR more stable than my BC, and my BC will be replaced in short order. The advantage of the BP/W setup is that the webbing harness is infinitely adjustable, very easily, and without any tools. The shoulder straps can be put as narrow as you want (crossed) or in a more standard place. The waist band is easy to get snug. It just customizes more easily.
Just my personal experience . . .