I've got an original run of these boxes and I've used them with the Sito. It was touching the boxes so I ended up with a big ripple in the aluminum. I don't recommend trying it. Anything with a wide opening at the very back isn't likely to work since the opening at the back is less that 3".
Those racks look a lot beefier than the ones that came with my Jesse's. The sheet metal split on mine in Guatemala and I had to ride home with ropes holding them on. I saved that cool GS logo that was cut into 'em though and bolted them onto my lids.