UPDATE: The Kriega tank adapter is
not well suited for the large/wide FZ8 tank. I returned the adapter and plan to use the Kriega bags for the tail and the Cortech Super 2.0 8L magnetic smaller bag for the tank. Now I know why nobody uses this setup on the tank of an FZ8.
The challenges I see with the Kriega tank adpater system is its too short in length for an FZ8. When you remove the seat and secure the strap system and stretch the unit over the thank, the attachment straps get over-extended. In doing so, the velcro on the straps is exposed and will scratch your FZ8 tank. Also, the positioning is kind of funny. If you go too far back to avoid the air intake, the front straps are too short. If the Kriega adapter was a giant magnetic blanket you could strap the US10 or US20 bag to, it would be perfect.
Decided to go with the Cortech magnetic bag for the tank instead. Fitted several bags at the dealer to the FZ8 on the floor, personally I liked the way the Cortech magnetic fit best on the tank. We'll see how it goes.