Where can I use my ammeter to measure the current set by the current limit potentiometer?
Put a blank paper scale under the potentiometer knob. Put the ammeter on the output, set the amp limit and voltage to minimum, and  use something like a 120VAC 100W light bulb as a "soft short" or heavy load - about 9 ohms when cold.

Observe the amps, and turn up the volts to see if the amp limit is working (if it is the volts should not rise and the amps should not either) - record the amps, turn up the amp limit, observe while adjusting volts, record the amps again (record by writing on the paper label under the pot knob.)

I don't see another practical approach to having the LIMIT "displayed" (displaying the actual amps is easy.)