Hi,
The neck width at the zero fret is approximately 10 mm and approximately 15 mm at the 12th fret..
I’m not sure about the thickness of the neck but I can assure you that it’s one of the slimmest and easiest necks i’ve ever played, i’m extremely fussy and have had a million basses over the years and this is one of the easiest and best playing basses that I haver owned.. I too have small hands..