My head is 23.5" around
after FFS.

I can't fit in any regular-sized women's hats. I have nipple-length long hair, and very little of it covers my forehead.
But I pass almost all the time now. If you do get FFS your head will end up looking much smaller than mine.
I always had self-image issues with the size of my head vs body, even as a guy, and also with the size of my ears. In the end, I was being unnecessarily hard on myself because it wasn't as 'big' an issue as I imagined. Forehead prominence can play a big part, although when I look around now at other people I'm seeing a lot of cis women with prominent brows. In my case it was partially FFS and the rest doing the best I could to polish off my image and all the other subtle cues that have tipped the balance in my favour.
I work in retail, so I get hundreds of interactions in a day where customers are verbally identifying me in conversation. Our uniform is a bit 'de-feminizing' so I get a lot of people calling out 'sir' to my back but then correcting themselves when I turn around and they see my face. Even with my 6'1" height I'm rarely getting gendered wrong face-on.
I actually don't mind causing people a little confusion because if it forces them to think about it then it might actually help expand their perceptions of what constitutes a 'normal' female. In the weird retail power dynamic between staff and customer it actually gives my the upper hand in an interaction because any uncertainty the customer might have throws off their confidence in trying to talk down to me. It makes my confidence look stronger than their's. I must say though that the change in how nice people are to me, now that I present and am seen as a woman, has been dramatic.