42" would work. I used the 60 on my JK with 35's. When raising my TH with a floor jack, I was suprised on how much travel there was before the front tire lifted from the ground.
2014 Trailhawk. Bright White exterior. Black Leather interior. V6. All available options (Cold Weather, Comfort / Convience, Sunroof, tow package, hood decal, Nav radio, 9 speaker sound system) , 245/70/17 Firestone Mud Terrains, BVG roof rack, LED fog lamps, LED interior lamps, LED back up bulbs, hood decal pinstripe, rear mounted hitch tire carrier, AFE Cold Air Intake