I have the Cycle-istiC luggage rack and a Givi with the bracket that attaches to a standard luggage rack. (Called the Monolock series. Mine is 30 liter.). Won't work on any other luggage rack. Believe I have tried them all over the last 17 years. Also have the Corbin seat so can use their backrest. You can also see that in the pic.
The pic shows a Nelson-Rigg soft bag mounted on the rack. Don't have a pic of the Givi on the rack. You can see the plastic Givi mounting bracket sticking out from under the soft bag at the back of the rack. It bolts to the luggage rack. I leave it on and just put whatever bag I need on it. I have 3 Nelson-Rigg bags of different sizes plus the Givi.