I've almost the same size wrists as yours and i'd say 44mm Pams fit decently on my wrists. Somehow able to pull off 44mm ROOs too. I guess it depends on whether you have flat wrists or not though.
I must have the smallest wrists ever, I just measured mine at 5.8". So i'm guessing my only options are 40mm or less which I've been researching for a while now but can't find many quality ones other than the rolex seadweller. Anyone else have wrists smaller than 6" and have a recommendation on a good rep?