I'm mounting a yak rack on my camper shell and I'm trying to decide if I should use risers or not. My shell is flat on top (as opposed to sloped) and I've got some of the brackets that simulate rain gutters which mount on the side of the shell. I've also got 2 risers, can't decide if I should use the 2, get 4, or use none. Anyways, does anyone have a setup like this, with or without risers, and does your boat/cockpit hit the top of the shell, clear the shell easily, etc. Any advice would be appreciated.