ILC,
I would talk it over with your doctor. My endo, who has considerable experience with MTF transgender folks, has me on estrogen only, through pills. My natural T levels were low, so I am well within the female hormone levels, and I am not on any t blockers.
I have been on E for a year and a half, and on my current full dose for 9 months. My doctor does not see this as too risky, although he does run liver function tests.
Best,
C