Voltage Transformer for 3 Phase Australia

Looking at using 3 of these voltage transformers for my 3 phase install in Australia, reasonably priced at AU$12.50 from Jaycar. Will be installing them into an enclosure & hard wiring to the 3 phases and neutral.

1: They are multi voltage tapped, should I use the full 15v tapping?
Will phase shifting be lower if using the full secondary coil rather the the intermediate taps?

Should be low phase shift as they weigh in at 665g ( 23 Oz). Apparently the bigger the better.
2: I will be using HWCT-004’s (known phase shift) CT’s, should I use the browser url: iotawatt.local/command?vtphase=3 to obtain a measure of the relative phase difference between CT and VT. Or can it be done between the 3 VT’s?

I would be spending the extra $52.35 overall, thus getting away from hard wiring, and a lot easier to replace if one fails, and you also need to buy plugs and cabling and enclosure for 3 transformers, would there be any real savings?

I’m sparky, hard wired iaw AS easy to do, got plenty of enclosures sitting around.
Agree, if you had to pay a sparky to do it then not worth it.

Max input is about15VAC RMS. IoTaWatt, 13KOhm will see the “ no load” voltage which is usually higher than the spec voltage. I would recommend the 8.5V or 9.5V tap.

I don’t know. I doubt it would be significantly different.