I normally wear a 34 in most, 36 in Resolute.
The 47 is generally smaller fitting. So for me 36 would be recommended, thus for you I'd say 34.You might get away with a 32, but it could be tight. Not sure.
edit: I just saw, that there is also a W33 availble. That might your best option.
Some retailers have the 47 in non/wash.
I didn't find them very stretchy. But of course the o/w will stretch quite a bit in waist.