A year ago, no HRT, @200 pound, maybe just under an A cup (moobs)
Now, 7 weeks into E-only HRT, @145 pound, working towards an A cup. The areola is expanding slowly, and is usually fairly puffy. I can feel new ducts and glands, and the breasts are getting that fatty tissue.
Perhaps I was pre-disposed to breast development though. I had breast development as a child. At about 12yo or so, I had the 'walnut' sized gland under each nipple, and they were sore back then. That was the limit of the growth sadly, and those glands slowly shrunk over the years into nothingness. With E now, it took about three weeks for those glands to return to their former state.