Here is a Good Way to do this:
NOTES:
The Higher your Known Test Current the Greater the overall Accuracy.
As to the Length or Size of the Shunt:
Any Length
that will allow reasonable Readings as Shown.
IF your SHUNT is TOO LONG, you will need to Adjust the Control Down LOW, Or BETTER YET,
SHORTEN the SHUNT.
IF you Can't get it to Adjust to these Readings, You need a LONGER Shunt.
Since Two SEPERATE Connections are made for the Power Connections and the Meter Connections, There is No Error from solder connections as mentioned in that other article.
Different Materials will have Different Resistances for the Same Area.
And Some materials Change Resistance GREATLY with Temperature.
Other QUESTIONS?, Just ASK.
Gary