That clamp bracket setup is not made for this gutter. It's evident by looking at the side-view picture.
You can probably get away with spacing it out with a longer/bent bolt but then you're shifting the load across a longer bolt/washers.
It's a very poor design to begin with because the tighter you go, the more stress you're putting on the bend on the bolt.
The L-shaped foot bracket looks like it's made for a light-weight load (ie. 150 lbs max). I can't see any reinforcements on it.
Looking at the angled section that points down into the gutter, it has been modified to clear that van body.
Not trying to be a bummer but I would hate to see someone overload a rack and watch their gear sprawling out on the door through their rearview mirror. I've seen it happen on a trail run.
It doesn't look like this rack was made for this type of vehicle going by your pictures.
My 2 cents.
This is the type of footprint/clamp the high roof should have.
EnviroImports.com wrote:

Or something like this