We have installed the retrax pro cover as well with rambar, our OEM factory installed rambar has bolts on top (is this something only some trucks have?). It fits JUST barely inside the bolts.
We added foam along the front edge all the way back about 3/4 of the way around the sides for waterproofing. In addition we added a very small piece at the rambar to truck bed side transition. I have some black caulk to touch up a couple areas such at the front corners.
The tailgate area we used a peel and stick seal but I am uncertain how waterproof we can make this. I ordered another tailgate seal to play around with. This is not specific to the rambar so it seems like a solvable issue I might ask the dealer to help out with.
One thing I noticed about the retrax that is a little annoying is that when closing it you need to open the tailgate to tug on the opposite side of the cover to fully extend it for sealing, otherwise it leaves a tiny gap on that side.
The ram installed side utility bars will also not function properly with this cover. The notched opening at the front of the bed is behind the side of the box for the cover, so you cannot remove or install anything already on the bar. It shouldn’t be a problem for us, what do people use these for? I bought the mopar cargo organizer but returning it as it will not properly fit with this cover either.