I'd shoot for a 35 on a 9.5" wide 24. 12mm would put you at the outerfender and 50 would tuck you to the max but you might have a little tire rub on the inside.
who makes a wheel with that much offset?
all i can seem to find is +12 and +18 nothng over that. id really like to stay away from having custom wheels made for price reasons