If "the big surgery" means full SRS then it is not as important as it once was. Sure, it would be great to have full female parts (labia, vagina, clitoris, etc.); but since I don't have any intention to have sex with a man and due to my age less could be acceptable.
The minimum acceptable could be total removal of the penis, scrotum, and testicles with a proper urethra relocation like a female. Also, body and facial feminization to the a passable degree so I could present as female on occasion without question.
However, labia would be nice for effect and to limit splashing.