i have discussed this in other forum posts, but i would suggest that you take a look at using an herbal supplement. the one that a lot of trans use is called purearia milifica. it is a pretty potent herbal. used by a lot of trans in thailand as opposed to pharma grade hormones. a good brand to use is called ainterol. yes you do get feminized. but you will get a sweet pair of man boobs!
A lot of it has to come down to genetics and hormones. I developed mine around puberty and they've only gotten bigger the fatter I have gotten. Currently at a 46D. I've heard some herbal supplements work, but I would proceed with caution.