This shows one way to get a base rail onto a VW Crafter 2017-2021. I used Rhino-Rack branded roof rails. These use a very common T-slot to add things (a rack ) to the roof.
On top of this rail I have now installed a 8020 (30x30) Aluminium extrusion rack /box that lifts my 2 domestic 370w each solar panels. with room for a roof top seating area while not interfering with two maxx air fans.
