Roof rib gap help

[gmflash88]

So my roof is riveted in on the edges and the middle only. When viewed from above, there's a seam down the center line from front to back and that is riveted into the ribs. What this means is that there is a notable gap between the roof steel and the ribs inside.

It seems that my only option is to shim this gap and add fasteners to allow me to run unistrut lengthwise to create a rack for my solar panels.

Has anyone run into this before?

Thanks!