Seeking Rooftop Deck Advice

I just bought a van and I’m going to start building it out soon. I’m planning on building a rooftop deck, but I’m a little worried that the wind will catch the bottom of the boards and either fall apart on the highway or make driving really difficult.

Anyone here done anything like this? I have a '98 Econoline Club Wagon. Going to attach a few ladder racks to the gutter rail and bolt some deck boards to the crossrails. Should be pretty easy, but I don’t want to find out the hard way that it’s not functional.

Doing the same thing; however, I’m going with expanded metal framed with 1” angle iron due to that same concern.