It all depends on your build, what you were previously, how much of it was fatty tissue and how much you work on your pectoral muscle area. I'm not sure if my specs will help but,
(Note: I'm still not on T nor am I at my physical peak)
Before 5'10" 225lbs I was a 40C
Now 5'10" 180lbs I'm a 36A or 36B depending on brand
Unfortunately, I found out I can't bind due to my ribcage shape v.v so I have put a lot of focus on reducing my breast size and utilizing sports bras. but if you're doing a lot of upper body workouts, that will help with decreasing that annoying upper fleshyness