Just had the (very short) meeting.
She seemed to just dismiss it as not a big deal, they have a strong nondiscrimination policy and will be accommodating. I was in shock because I expected a barrage of questions. She said there were like 1-2 people she know who have transitioned on the job and when it gets closer, talk to my manager and arrange the date I go full time at work. I asked about bathrooms and she said just use the one you present as.
Her only concern was time off for things like surgery but that's not on the radar yet.
I also asked if insurance covers trans care, she said that open enrollment is in a couple of weeks and I could ask.
All she said is that they care about performance at work and as long as that's fine (it should be) then I'll be fine.
She also said best of luck.

So no, I'm not going to just show up at the office (or on set or in a control room) dressed up en femme... but when I go full time it won't be a shock to everyone either.