am fairly sure that no matter how masculine-of-centre I dress the vast majority of people are going to look at me and see a she

Honestly I thought that too and have been surprised at how little effort gets me called "he" or "mate" or little kids saying stuff like "why does that man have a stick?"

Which is not to say you should or have to do that. But it might not be as out of the question as you imagine. :)

I'm sorry you can't make your announcement yet! Happy they/them pronouns, anyway.