You have 17x7.5's. You can technically fit 285/70/17's on your wheels but will experience HEAVY rubbing due to the specification of the wheel.
I would highly recommend that you get the 16x8 with the proper settings (4.5 Backspacing and 0 offset) and then pick up some 285/75/16's.
The biggest reason to get 16's vs 17's? PRICE. 285's in 16's are MUCH cheaper than 285's in 17's. Also wheel prices come down significantly. Lastly, when you offroad, the more sidewall you have the better you are so with 16's you have abit more sidewall than 17's.
Good luck