Clockman,
I think I will persevere with that 200A ACS758 hall sensor for measuring DC current into the OZ inverter. At least until I get the Deltec shunt and parts directly connected to the Mega.
When I was bench testing my OZinverter I checked the DC current usage while running different AC loads using a Deltec 500/50 shunt connected to a Midnite WBjr wired into one of my Classic150 controllers. Using an Arduino DUE based web server and extracting modbus register values for WBjr data. This worked well and avoided the need for more DC current sensors.
I even went as far as using my spare Mega with the OpenenergyMonitor interface shield to measure AC volts/amps and Hz then via IC2 connection to Arduino DUE web server, sent this data for display in my main web page.
It was a nice and easy solution if, like me, you want an integrated web monitoring system showing all power generating details (PV and WInd turbine) as well as output power details (Inverter info, hot water heating power diversion) and battery bank state monitoring.
It seems the INA219 can't easily be adapted for use here, its max voltage is an issue that does not appear to be easily resolved.
dgd