Agree with above post. Just use a shortie tri-suit/skin-suit or just tri-shorts and singlet. To be honest - with the exception of the 'bathing-suit' style suits, men's and women's suits generally look similar (I know some smaller built guys who will use a woman's skinsuit, simply because it fits, is cheaper, or both). Since you're pre-op, would recommend black-colored suits to help hide the shadows (I guess also depends how built you are there).
One other thing - since you'll get your name and gender marker changed, prior to competing - I would also check with the race organizer AND the sanctioning body (i.e., I'm in the USA, so I verify with USTA) regarding which gender division you can/should/will compete under. It's not so simple as showing your government ID and assuming you can straight away compete in the women's division...there will be questions...sometimes many, many questions, sometimes nasty questions...even at the bottom tier/newbie tris (unless, of course, if you already pass and simply and inconspicuously blend in with the other women at pick-up and line-up).
Good luck and keep us posted!
