Grounding Quattro and Lynx

DIY
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1

This may seem stupid, but I am having trouble understanding the grounding of the Quattro and Lynx systems on a boat. We have a 48v battery bank connected to the Power In, a smart shunt, and two distributors. I have a central ground running from the Lynx system to the main DC busbar (from one of the two distributors) and grounded to a plate on the outside of the boat. We also run our AC through an ELCI and have grounded the AC panels to the DC ground. All AC lines are attached to this, including the AC lines running in and out of the Quattro. My problem is with the Quattro primary ground attached to the chassis. Do I connect this to, say, the ground point of the other distributor to make sure the Quattro is grounded? I am getting lost in considerations of grounding loops and other things and just need to know how to attach