So having a spare did you go with wheel spacers in back?
IMO - the spare is to get you back to the trailer, the buggy won't care what offset the wheel has. I happened to be out without either of my spares, hit a sharp rock and had to borrow a buddy's spare which was 3-1/2" taller than my tires. (32" to my 28-1/2"). Luckily, it was a front tire, I didn't use i4wd except for a couple of iffy situations and the computer never figured out that there was a rather large size difference between the two tires. You couldn't do that on the rear since it's effectively a solid axle and the 'scrub' would be an issue.
ETA: we would have taken the time to put the large tire on the front, regardless of which one I had damaged because we were 30 miles from camp.