Will you need to use inner tubes? Some of the old wheels had rivets that were not intended to seal the rim.
Lots of owners in the US have switched to radials..... for several reasons, better availabity, ride better, and they track better.
My '39 Buick with belted tires would follow whatever groove was in the road, just annoying.
I don't think the size matters as long a you don't have a clearance problem..
There is also those that would argue about putting WSW on a pre WWII vehicle, few low priced cars came with them so sometimes
WSW on those cars look out of place....... however I vote for WSW if you could get them.