what size tyres on fourtrak?


hello everyone
got myself a f70 fourtrak with pants tyres, and i want some big agresive mud terrains.
would realy like some 33" but not sure what hight to lift it? it's had a 2" spring lift at the back and i'm giving it a 2" shackel lift at the front.
will 31"s look to small or will 33"s need more lift to wedge them in?
thanks for any help