[Dynsei]

Which hormone regulating herbs to take during menstrual, ovulation and luteal phases. This http://aje.oxfordjournals.org/content/145/7/571.full.pdf (Medline) gives a good picture of which hormones maintain size during which time.

Taking another look at this solves more pieces of the puzzle, with the newer information.

From the abstract, hormones associated with breast size: (my conclusion in parenthesis)
Days 5-10; 18-23: birth control pills
follicular: high IGF-1
luteal: high progestins (activating PRB), high estrogens (ERα), low androgens
days 18-23: low progestins (PRB)

for users of bcp days 5-10: high prolactin, high LH, low FSH (required with high PRB activating progestins)
body size has to do with breast size, but not in bcp users

Results section (some of this is from discussion section):
follicular phase: high prolactin, high IGF-1
luteal phase: high estrogens, progestins and prolactin; low FSH, low androgens
days 5-10: low FSH; high LH, high prolactin

Discussion:
IGF-1 explains why body size, excluding height, is correlated to breast size
high LH, low FSH

(Discussion section continued...)

(correction, bcp contains both progestogens and estrogens)