Suggested ratings should be listed in your manual. The side rails hold more than the floor rails according to my manual which surprised me, although I have forgotten the exact numbers being an '05.
Moving 4' x 8' stock I use the bed cut outs and 2x6 or 8s to elevate the load above the wheel wells in a factory sprayed bed (not plastic bed liner insert).
Moving 4' x 8' stock I use the bed cut outs and 2x6 or 8s to elevate the load above the wheel wells in a factory sprayed bed (not plastic bed liner insert).
