Why not to give more estradiol? Because largest estradiol pills nowadays are 2 mg. One pill a day according to the gospel (package insert) does nothing for MtF. No doctor would prescribe more than 4 pills a day. Medical school is cramming huge amount of info. Doctors aren't used to dig for numbers and to think by themselves. They blindly believe other doctors' opinions. No doctor managed to dig for numbers and calculate: birth control pills prescribed to over hundred million women contain ethinylestradiol 0.03 mg/day which affects liver and blood clotting 500 times stronger than oral estradiol, so risk from oral estradiol 0.03*500= 15 mg/day is considered acceptable. But estradiol 15 mg/day is 8 pills per day - seems too much for doctors. Simple arithmetic is alien science for them.
I'm an engineer, I'm not afraid of arithmetic.