I run the regular ITP offsets for trails & work fine for me. They are soft so I've bent a couple rims while riding hard & hitting sharp rocks. I just air'd up a bit & took care of the dent with a rubber mallot. No prob's since. Offsets work great on stock arms & axles. Sit's you a bit wider & you can't complain when hauling ass thru those fire roads, they come in very handy!!
I run the ITP C Series in the sand, they're a stronger wheel but I won't dare take my nice PC rims into that rocky stuff.