My Famsa frame was secured very tightly, it held my sheepy in place with no other restraints. I would have found it hard to un clip the bag each time fuelling up. All I did was unzip to the edge of the seat on the lhs and flip the bag over, basically the same as this....

The picture is the new GL bag but same result only the GL bag has two zips not one so I can choose which to zip depending on situation etc but I couldn't with the Famsa. Pretty quick and easy, just remember to keep the bag closed when flipping
I paid $295au for the Fandango Pro, it's 8l where the Diablo is 4l...couldn't imagine only 4l since the Famsa was 20l extended. I was surprised how much room the 8l has since a lot of the Famsa volume was in the side pockets the insides of both are not that much different. It's the outside the GL is worlds apart, slim and tapers back towards the handle bars...

Haven't been Offroad yet but basically in standing position I didn't find myself hitting the bag at all!!
Additionally love the secret pocket, through cable access and front mesh pocket of the Pro over standard, worth it in my opinion.

All in all stoked and that's not even mentioning how well the pannier pockets fit and sit

Matt.