Damion, how did you get a nut behind the bed? Also, There is no interferance with the bed lamps?
I dropped my wheel well liners, removed both tail lights and reached in between the outer bedside and the inner box panels. Im not saying there was tons of room or it was super easy to do, but it is doable. I may have even created a few new yoga poses too.
It does take 2 people to do this though, one in the bed holding the bars, and holding the bolts in the hole / having a ratchet to tighten them once the nuts and washers are put on inside by the second person. I had my dad in the bed with an electric impact gun while I was under the truck with a wrench starting the nuts.
Theres ALL kinds of room for the bed lamps. No worries there. The nut washer system probably doesn't stick out much more than the real insert system does.