Roof rack with slats for an Access Cab carrying a propane tank

I have a 2014 Access cab and am looking to carry a propane tank on the roof for a Propex heater to be installed in the bed. My truck also has an ARE MX Shell (the one with the higher ceiling) with a Yakima rack, but I figured having the rack on the cab rather than on the shell would keep the total height of the vehicle lower when the propane tank is absent. (I encounter some low-ceiling parking structures in the city every once in a while.) It looks like this upright propane tank holder might work, assuming I could find a rack fitting an Access cab with slats. Does anyone know of such a rack, or have any experience externally carrying a propane tank with an Access cab? Any advice would be appreciated. I guess another concern would be running the gas line from the cab into the bed, while not having vibrations shake loose or wear down anything.

I've also heard of swing-out carriers on the bumper, but I have to open the tail gate often in parking lots and it seems having the carrier swung out might get in the way in a cramped lot.

 

Check out prinsu racks.