I have just searched the "dual Steca Grid 3000 inverters" and found it is just a grid-tie inverter with two single-phase outputs, yes?
If so, I think it is used in the single-phase three wires system, yes?
if it is indeed 1 phase 3 wires system?
If so, you can use any two phases of WEM3080T to measure it.
(if you just want to measure one or two circuit loops, you do not need to connect all three phases of WEM3080T. Because the three-phase energy meter ( WEM3080T) also supports split-phase usage which means you can use it as three single-phase energy meters.)
Besides the WEM3080T, there is also a cost-effective method, using one phase energy meter WEM3080 to measure the single-phase 3 wires system.