I have 6.5 inch wrists and loved the fit if the 243. The others are just too big. Your wrists are even smaller than mine, so I think you should skip the 47mm models.
The one thing to really think about is the thickness. It is a beast. Same can be said about the 64 and 87 (also choices you should consider if you don't mind going pre-owned). Otherwise, also look into the 24 and 25. They are thinner.
I'm still holding out some hope (perhaps foolishly) that a future SIHH will offer new 44mm submersible models.