I think the Madrock Safeguard was designed and intended as a rappel device. I don't think it was designed for saddle hunters to hunt off of it. But we are using it for that purpose. It was not designed to be used with 8mm rope, but we are doing that too.
I have read the information provided with the device. And at the end of the day, I run a Sterling HollowBlock2 (auto block backup) on either Sterling Canyon IV 9mm or Samson Predator 11.4mm rope attached to my linemen loop and will continue to do so. Just makes me feel safer going up, hunting, and coming down.