There are very experienced endos and clinics who do not do tests often.
They check for vital signs, how people feel, and how feminization progresses.
Its not a process where you can simply measure levels and all people have the same results.
Basically what is measured with tests are free levels, available in the blood.
Levels of substances absorbed cannot be measured.
If you feel you have not sufficient feminization, or if you do not feel well you should tell them.
But as said its not solely dependent on numbers.
A tolerance should be very rare.
Do you still have feminization, boobies itching from time to time and having growth, delicate skin etc ?
hugs