So I have a hardshell RTT that has the mounting track built into the bottom fiberglass and they run the same direction as the side rails of the roof rack. I would like to avoid another set of rails adding more height and another connection point so I would like to mount to the cross bars. I have not looked into this yet, is it well know that the cross bars are not strong enough to support the tent, wonder if I got a third crossbar if that would spread out the load enough?