Well im no expert and dont want to give any false info...But the link I posted said backspacing of 4.25-4.50 will work with some rubbing.Now is 5.50 backspacing going to work I dont know sorry bro maybe someone will step in and help here
I would love to know the answer I also plan to get 37x13.50r20 tires the nitto mud grapplers on stock H2 giong to try the rim backspaceing recomended in that link on some rockstars and hope it works
as far as width gor,people put 35x12.50's on 8" wheels,so you are only 3 wider then wheel,you will be good on that part,but the backspacing would scare me a bit