I am having similar thoughts myself. For career reasons, I will continue to present as male for the next couple of years probably even though I am starting HRT.
At present, what is important to me is who I feel like inside. Am i being true to myself. That is what seems to be important.
I can't see the attributes that are most important to me changing, that is my ethics, empathy for others, and general beliefs.
I am not so sure about GRS. As a married person who is unlikely to change orientation, a new canal would go unused (maybe I lack imagination). Testes though are a symbol of the masculine for me much more than the phallus. Penis == Big Clit.
So, I guess we all have to work out what is important to us. How we see ourselves is important, but do you see yourself in the reflection of other people's eyes or through your own.
How much do you feel you right now? How much does it matter to you what those close to you think? Does it matter to you what strangers think?
For me, I think as long as there are not too many things that are too overtly masculine, things that break me out of my self image of what I should be, I will be ok. Testes, facial and body hair, and general body shape are high on my list.
Going further also conflicts with my other goal of not retiring on the poverty line.