Old topic, but in case you are still wondering...
My research has shown that you can reverse it in that you can get expanders put in the way that a woman who gets implants after a mastectomy does prior to reconstruction (if she doens't get reconstruction at the time of mastectomy). From there they will expand the skin over a period of time and then put in a silicone/saline implant. The problem is that most implants they make are a C are larger because most women who want implants are looking for at least a C. Subsequently, if you would prefer a breast size smaller than a C, you may have a hard time finding that.
I would suggest meeting with a surgeon (any plastic surgeon who does breast reduction will do), and find out how small s/he can get your chest with a normal reduction. From there, make your decision.
One other problem you may run into is if you get free nipple grafts at the time of your top surgery, they will be in the "male placement" when you get the reconstruction/breast augmentation. My understanding is that they cannot be removed/moved somewhere else again. You should look at pics of transwomen who got breast implants to see nipple placement.
Good Luck.