An open category carveout for trans athletes isn't the way I would have done it.
I would have kept two divisions, and just did a bit of a rename. Open (for what is currently the male division, plus a few extras), and Restricted (for the female division, plus a few extras).
Open for cis men, trans females with fully functional male hormones (or who had a male puberty even if they're now on hormone replacement), etc. Maaaaybe allow a certain subset of trans males that have had male hormone replacement, up to sensible limits of testosterone levels. Though it's tough to imagine them being able to compete with cis males.
Restricted for cis women and trans men with fully functional female hormone levels and no significant amount of male hormone replacement in their history. Maaaybe allow some trans females if they've had a verifiably complete hormone replacment dating from before and all the way through puberty, though I'm not certain about this last group.
Also, maybe there's some room in the restricted division for some of the really rare cases, like XY with angrogen insensitivity. I believe there's one of these competing in track and field on the women's side, from India.