I don't know that this will be of any help be here goes.
When I wanted to fit panniers to my FZS600 I got some Non-Fango panniers cheap only to find I couldn't get any fixing brackets to suite my bike. I ended up making my own and still keeping my Givi topbox arms etc for support at the back. Shown in these photo's.
I decided later these panniers where to big and heavy, probably because I always ended up filling them.
I now have the small Givi panniers and modified my brackets to suite them. Again I couldn't find any Givi brackets available to suite the FZS600 bike.
I now travel lighter on my camping trips etc. and still survive without too much hardship.