This is something I'm very interested in myself, as I'm not sure when I'm going to start T and I have two goals before ever having top surgery:
1) Lower fat down to a healthy range. Right now, I'm about 168lbs which would be great...if I wasn't 5'2''.
2) Bulk and build muscle. Unlike a few of my fellow transmen, I want to be bigger when it comes to muscles. I've always wanted a healthy, fit body with plenty of strength.
My personal hope- as vain as it may seem- is to work on my muscle mass, especially in my arms since I'll be strumming for some time and I rather like my arms despite my current biceps being a bit lacking.
Hopefully this is something I can take part in as well for my chest, as anything which makes binding 36 B's easier would be wonderful!