Hi,
I use Rhino bars on my Land Rover, one pair for my roof top tent, and have a second set for carrying two sea-kayaks. I have given them hell, I rubbed them against a cliff with the weight of the vehicle leaning on them, it made the legs slide along the vehicle gutters ~8 inches, and the legs survived. The ends of the Al cross bars were a bit messed up but I just sawed it short, still fit.
No experience with the tray, sorry.