Hello.
Measuring the resistance of the motor is a good first approximation. However, in general it is difficult to measure small resistances accurately. A better way is to measure the amount of current that is drawn at some voltage and compute the resistance. Try stalling the motor at some small voltage and measure both the current that it draws and the voltage drop across the motor (this might be less than your unloaded supply voltage if the current draw causes the supply voltage to drop). With those values you can compute the resistance using Ohm’s law, and then use this in turn to calculate the stall current at higher voltages.
With the load you described, and the readings you have to date, I suspect the stall current of your motor will be more than what the 24V23 can handle.
-Derrill