As part of my original purchase of the bike, I included the GIVI racks and 3 boxes...two 33l and one 42L. They were about the only option to the Honda panniers at that time. The boxes have served me well, but I've never like the method of opening. They have a new box, the dolomiti that is promising. Nothing is cheap.
when I had my nighthawk, I took an EBAY rack for a V-strom and some military surplus mermite cans and make panniers. Someone once thought I was riding a BMW because they associated aluminum cans with the brand.
If you haven't watched Mondo Enduro, see if you can find it. those guys were great at making do on a round the world trip.
Link to the build.
The Adventures of an Old Fat White Guy: Mermite Panniers - Part 7