Threaded holes in Beef Bar

I am trying to come up with a Load Stop on my gfc camper beef bars. I design and build houses for a living and occasionally need to strap lumber to my rack. I had Yakima load stops on my Leer top and they worked. But the Beef Bar has presented a new challenge. Can anyone tell me about the non used threaded holes on my Beef Bars are for?

My understanding is they are AMPS 2-hole pattern, mostly used for RAM style ball mounts or other accessory mounting (lights, etc).

I am in the same boat with needing a good spot to latch tie downs too. I was thinking of mounting some eyelets to those holes somehow but do not know the thread sizing. did you come up with a solution?

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