I usually go to the gym at Davis-Monthan Air Force Base just before my counselor meeting. Since I don't know how the military will react to it, I've always dressed male. However, I have some semi-permanent...um... appearance modifications that are tell-tale, to wit: I have long hair, polished acrylic nails, and a gold stud in each ear.
The point being, on those days, I'll dress in male clothes. The two other times I went to my counselor, I went completely "en femme". My counselor mentioned that in my letter to my physicians.