Hello,
I am male to female trans, intersex woman. I am 62 years on.
In order to see physical changes you need estrogen levels equal to a teenager in puberty. Changes take three to five years to complete as they do in puberty. Progesterone Im told should begin about a year after estrogen starts. Progesterone and estrogen work together. Not just for breast development, but also heart and bone health, and likely more.
I personally take estrogen by weekly injection at .06ml. But each persons requirement is different. Im told blockers are bad for me. If you are intending to transition, why not just remove the source of testosterone and skip the blockers all together ?