Flipped it around as you can see the pins don't go down all the way. That being said it's still sturdy enough.... Might leave it in this way.
I have both Kreiga Us20 +US10 and a Ventura rack If you have a pillion seat I would put that on rather than what you have there when using the Ventura
I used to travel with the pillion seat on mine when I used the Ventura rack. Then I had the rack platform at the back, and the bag sat on the pillion seat and the rack just stopped it from moving. The platform is then available for waterproofs etc via a couple of bungy cords. With it mounted like this, the rack isn't taking the weight of the bag.
Good decision on using Ventura, this was my 748 a few years ago on a 10 day trip to West coast of Ireland. Not cheap but rock solid and carried everything I needed. No effect at all on the handling and rock solid at all speeds.