How to measure current at output port
Output Pin &lt;=> Multimeter &lt;=> Resistor &lt;=> Ground(mounting hole in the board/power ground)


Yes, this is essentially correct.

If it's not too late, re-design your circuit to have two output terminals instead of one, with the second terminal being the ground or return terminal. This will save you having to connect your circuit to its load using a mounting hole.

Choose the resistor value depending on what compliance voltage (maximum output voltage) your current source is specified for. For example if the specification is 10 V compliance, then use a 100 ohm resistor. If the specification is 1 V compliance, use a 10 ohm resistor, etc.