A lot of the attitudes of the physicians is dependant on themselves. Most tend to run to the conservative side. If I had to guess I'd say too conservative.
Evidence available to MTFs is based on hrt dosages for menopausal women, often enough, and the "levels" shown by labs and reported in ranges of "prevalence" in the bloodstream are invariably based on women who have, from birth, ovaries and adrenal glands that produce estrogen as a default. Most I've met will tell you just exactly that.
And they tend to be fearful of going above certain fairly low limits.
Try doing some work on your own like checking out some of the mtf hrt list serves that are, as far as I am aware, free and open discussions. Even if you have to request membership they should, normally, be open to allowing newcomers into the group.
They can be very valuable, but as with anything you read on the web, take some of what's said with a grain of salt. Take other things you may read with a box of salt.
There's no point in compromising your health. But, there's no point in compromising your hrt either. But in large part it's going to be something you're going to have to do: the research. And make sure you can cite chapter and verse when you present to your endo/GP.
The research into actual changes and hormone dosages etc and effects and side-effects for mtfs is not voluminous, in fact it's rather meager and the list serves prolly keep up with what is there better than the doctors do. The docs are usually very busy making livings and research isn't usually a huge portion of it.
I did find that my doctors were willing to listen and read when I could hand them something factual or at least researched by another MD.
Nichole