I actually contacted the guy who makes these a while back when trying to think ahead about my first window-cover project (still waiting on the van delivery).
The designer owns a passenger wagon Transit himself, and he says he loves it. I contacted him because I was curious why they suggested their "suction cup" versions with passenger wagons while the cargo vans could use the neodymium magnets. The magnets have obvious advantages.
He said the interior trim gets in the way of the magnets. I was basically already imagining his exact design when I found his product. It's quite pricy, and I was looking forward to learning about sewing and materials. I'm interested to experiment with magnets with the factory interior trim.
If I ever get this van, I will share what I learn!