That Cade light mount is expensive. You can get a Chihiros led light for the same price as the mount
Maybe search this forum in the DIY section as i believe some people have done some hanging mounts with parts from Bunnings. The connect-it as you say might be a bit weak but surely Bunnings has some other parts you could use.
You could possibly do it for half the price of the Cade with Bunnings parts. However if you want it now and rather be safe since the Cade should definitely hold the light then just stick with the Cade.