The whole recommendation regarding lower one's E dose post-SRS is pure BS. It's based purely on conjecture, not actual labs, physiology and biology. If you required X amount of E to maintain your E2 levels at a certain point after 2 or more years of HRT while preop... removal of the testes or SRS will not change your required dosage. Rely on your lab work, specifically your E2 serum level, and your own personal physiology. HRT is not a one-size-fits-all prescription.
In my case, my E dosage has remained exactly the same after my SRS. Which is still near the max "recommended" dosage of sublingual oral E. And my E2 levels have remained constant. Rely on science, not supposition.