I've seen that size on a stock WK and it looks good. Unfortunately, Duratracs aren't available in that size.
Edit: 255/70r17 is 31.1" in diameter and 10" wide. 245/75r17 is 31.6" in diameter and 9.7" wide. 245/7r17 is 30.5" in diameter and also 9.7" wide.