Okay, when I installed the shunt, I put it just forward of the Battery Junction Block. I moved the factory made and installed negative cable from the negative terminal of the junction block to the shunt and installed a short jumper between the shunt and the junction block. When I installed the 4 gauge cables for the PD9260CV, I installed those directly to the junction block terminals also.
In the attached photo, you can see the PD9260CV but more importantly just above it you can see the shunt. I drew a yellow circle (difficult with a mouse and pc) around the factory cable on the shunt.
This allows any power that is going in or out of the battery to pass through the shunt. The charger wouldn't have to go through the shunt, other than to measure the efficiency of the converter set up. Since this information (current flow during charging) is not used to determine when to set the SOC (state of charge) to 100%.
In upgrading the batteries, I made all new cables for everything other than the inverter using 2/0 solid copper cables and crimped on the ends. So I no longer have the smaller gauge cables and poorly crimped ends. Yes, they are adequate for low power, but if you want to use the 1200 watt Inverter towards the upper end, they are not sufficient due to the wire size and low conductor count. I have thought a lot about upgrading the inverter but haven't convinced myself of the need, yet anyway.
Let me know if that helps, otherwise I can provide additional input and/or answer questions you may have.