Think not of the batteries as nodes, but the **wiring circuits** is what you are tapping into or extending.
The round-trip distance, the gauge of the wire, the devices and terminals in the path, creates a certain voltage drop at each location.
If the result is too low, either increase the wire gauge or move to a DC-DC charger placed near its target bank.
Where needed, a VSR/ACR prevents one circuit's loads from draining batteries designed to be used for another segment.
In some cases the DCDC acts to do this since it only allows current to flow in one direction.
But as above, the Renogy uniquely required a switch for that direction too.
Make a schematic rough drawing and post it, maybe worth starting a new thread to attract better / more responses.
There's another buncha smart codgers over on caravanners forum, tons of past threads there about exactly this scenario, and there do seem to be specific conventions in the Aussie community.
