I have an MQ Club Cab with a Carryboy canopy. I had to buy two pairs of roof racks; one for the cabin (using the built-in mounting points), and one for the canopy (which has longitudinal roof bars).
The roof racks are primarily for carrying long kayaks so I normally only use one rack on the cabin and one on the canopy.
I have some long (RHS) steel bars with padded V-shaped supports at each end to support the kayaks without risk of damage.
My question is: Is it okay to rigidly connect (via my steel bars) a roof rack on the cabin to one on the canopy, or should I account for some flex (of the chassis) between the two? I wouldn't like to be applying enough stress to the roof rack mounts to damage something... and then have my kayak fly of the roof at speed and spear through the windscreen of an oncoming car...