Do yourself a huge favour and forget the flare idea. I had Bushwacker flares on mine, they caused alot of damage by wearing through the paint and trapping fine crud/sand between the flare and the body which resulted in rust.
I never would have known the extent of the damage until it was extensive, and expensive. But I tore one off on some brush, the extent of the damage around each flare was not pretty. But for the most part I got before it was to serious.
I had the area the flares covered plus the entire lower body sides including the rocker panels and door insides coated in Linex.
Expensive yes, but I do not regret a penny of it. The Linex has stood up very well. It looks good and does a superb job of protecting the truck from whatever.
I posted pictures of it in a post in the spring of 08.
If your serious about protecting your truck forget the flares and get it Linexed.