AdaRac + Rolltop or Folding Bed Cover?

I called AdaRac hoping for a list of compatible bed covers, but no-go.
Is anybody successfully using AdaRac racks ( ) with a rolltop or solid folding bed
Seems like AdaRack's rail assemblies would have tb stacked on top of all the covers' rail assemblies that I've see so far.
For definition purposes: (folding solid) (rolltop)

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