I had no idea they're plastic. I did some digging and found that they're PA66 with 50% glass fiber. That makes them fairly sturdy. At least Kawasaki sprung for the good plastic. But it is also good to know that they are not metal. I think I'll sling the canopy across the passenger seat and use my rear canyon cages as the front anchor and the grab bars as the rear. I've had my fiance back there, so I know it'll hold at least that much.
I was kinda worried about going wide across the seat because of the saddle bags. I didn't want them supporting the weight of anything. I think I will just put something on the seat first to give it some space, and also make it so I can get in the bags without disassembling everything. This should be interesting.
Here's a pic of my ridiculousness. 4 of the heavy duty rokstraps holding it down.