It’s not necessary!Wolvyman went with a 1" spacer. I don't know if I really care about 3/4 of an inch on each side to make the back wheels match the front. My son uses spacers on his rzr and said every time he rides he hope one doesn't let loose. Do you really think it's necessary?
I guess I was confused, I thought he did 1.5. Less is better.
I used 1” on my Gen 1 to get square.
Bolted them on once and ran it like that for 5500 miles and never checked them. They never loosened. I use 2.5” spacers just for Moab and Sand Hollow and I do worry about them coming loose but so far so good.