start with 162 mains and 48 pilot, needle in the middle. i would work down from there. youll probably end up at 160 main and 45 pilot im guessing. in my experiences most of the PWK carbs all jet about the same way.
as far as the cub, my 4mm and 10mm cub motors ran with 39mm PWK have always been in that same range.
if you want a second opinion, why dont you just call Jeff and ask him?