Part 1:what do you mean by backspacing. different rims ??
PART 2: do you happen to know if u bolts same as I just ordered a set before I found out the other 59 rear
end also has excessive spider gear play.
thanks
Part 1: Yes, different rims may bring a wide or narrow WMS back to looking acceptable.. or live with it.
Part 2: If axle tube is same diameter (3"?) and using same springs and plate....yes.