I prefer the 2" with flat steel hooks, take the hooks down the outside of the rub rail and back up through a stake pocket hooking it on the outside edge. Won't come loose while you're strapping it down and will stay put should something happen on the road. 30' long will go over 5' diameter rolls double stacked top and bottom, 27' will go over a single row on top. Buy one and cut it off at 12' long, you'll be surprised at how handy it is without having to deal with 15' of tail all the time!
I've had good luck with the S-Line and Vulcan brands, for what it's worth.