Wiring Ammeter with Shunt Question, wiring size?

RoyB wrote:
Back in the day when we had multiple DC Meters to use we always put all of the DC Meters in series...

That's a great way to get a really bad reading. Good DC voltmeters have a very high input resistance. If you use two in series, you'll need to add the measured voltages to even get close. Try it.

Voltmeters connect in parallel. Current is measured in series. In this case, it's voltage across the shunt which is being measured.