Like this one https://www.ebay.co.uk/itm/600W-MPPT...0AAOSwNSZa1yHT

My only real concern would be testing the islanding and I think that could be done by plugging it via a power meter like this https://www.ebay.co.uk/itm/Plug-in-E...EAAOSwiUpa4rvy

Then unplugging the power meter from the grid (not the grid tie) and checking it immediatly displays zero volts.

Does that sound like a good idea ?

Any experiences anyone ?