Gaby and Eileen have some great pointers. (no pun intended)
I started with 9 months of OTC (mail-order) stuff called B.O. raw glandular made from "healthy" cows

(something like that)
The 9 months of adhering to the "found on internet" instructions, I say I really wasted 9 months of time, money and possibly health issues. I made the right decision to go the right way of counseling and visiting the Endo. At the first visit with my Endo I showed him the B.O. and he laughs. He told me he have seen many different "stuff" people take to try to grow boobies.
There really is no other way then doing it right with medical supervision and proper medication. And you are not only getting the girls, but the whole package, remember this. Most of witch comes before the girls are becoming visible.
I say either stick with breast forms, or go the proper healthy medical route.
Oops forgot to add...
2 to 3 cup sizes with P.F., or any kind of meds? Nah... in general with the proper Spiro and Estradiol dose, a one or two cup sizes is expected. And don't forget we (male bodied CC or TG's) have a larger ribcage then CIS gender girls, so we need more breast tissue to perceive the same size.

I am a woman of trans experience.