I added a Givi Monolock E370 Tech. It's about as big as I felt I could go with the 22 pound limit on my bike's factory carrier.
Not crazy about the Monolock, as it needs the key in it to close it, but at least it's lightweight.
It holds a 12 pack of Stone IPA and rib eye, so I no longer need the car to pick up some beer!
Shared album - Andy C - Google Photos