Thanks for the welcome! (One question: Does the captcha ever go away? I suck at captchas.)
I have spent an unreasonable amount of time in mostly-pointless Internet debates relating to gender identity. I've learned that a lot of people have very strict rules about terminology, and that if you know more than two or three people who have strict rules, you are going to find cases where they disagree. For instance, I know at least two people who think the adjective should definitely be "transgendered", and I've met at least one who says that's highly offensive and it should be "transgender". I've seen people insist on "transwoman" or insist on "woman", and I've seen people argue that "transwoman" is either more or less offensive than "MTF". I find this baffling, although I guess it's no different from any other area where people have conflicting social rules; it's just that this topic tends to be one where people have stronger feelings, and/or are being influenced by a noticably greater degree of general harassment on the issue.
Similarly, I've seen people insist with fierce outrage that it is horribly dehumanizing to depict a character in fiction as saying something like "I used to be a man", and I've seen people who describe themselves that way...
My current feeling is that in general, anyone whose life does not fit easily into a clear-cut category for gender and/or sex (and oh MAN do people love to fight about those words) is probably already having a sufficiently challenging time of things, and does not need to be yelled at for Doing It Wrong. So I take people at their words for their descriptions of their own experiences, and generally don't give that much weight to what they tell me about what it is possible that other people could ever experience.
I am currently under the impression that all simple theories of "this is how gender identity works" are wrong, because I am pretty sure that some people are having genuinely different experiences, and that attempts to simplify this to create simple "right answers" are doing more harm than good.
For a long time, I thought gender dysphoria was really weird, and I couldn't comprehend it. Then one day, I was talking to some people in IRC, and asking about why it would upset them for people to guess their gender wrong, and one of the other participants mentioned that it bugs her too. And she was cis. And I was totally mystified, because it had never occurred to me that people whose gender identity was automatically recognized by society in general would have feelings on the issue. At this point, I concluded that actually I was the weird one.

BTW, I'm autistic, and several of my friends are trans-and-autistic, and better yet, they are the sorts of people who think jokes which violate social boundaries are hilarious. So it's quite possible I will unintentionally give offense. Please feel free to let me know; I really have a very poor sense of what people are likely to think are reasonable boundaries, and I am even more confused because I've found that people don't even agree on that sometimes...