How to Test Allen Bradley PLC Analog Output Scaling?
I'd say you've got the right idea.

Make sure the HMI user setpoint scales correctly in the PLC. In other words, if the HMI reads 0 to 75 PSIG, you may want it to scale as an INT from 0 to 100 in the PLC. Verify that scaling is correct.

Then check that the INT is scaling the analog output properly. Force the INT from 0 to 100 and make sure your multimeter is reading 0 V to 10 V. I'd do some quick steps of 10 for 1 V increments.

Power up your regulator and set the min and max pressure points. Looks like 0 V corresponds to the min and 10 V corresponds to the max from the manual. I'd also connect that monitor to an analog input. Useful for developing a loss of pressure alarm.

Finally, you've got to check the whole loop. Punch in [0, 25, 50, 75] PSIG on the HMI, read a [0, 33, 67, 100] on the INT, getting [0, 3.3, 6.7, 10] V out, and read [0, 25, 50, 75] PSIG on the regulator. The regulator pressure may not be perfectly linear, [0, 24, 48, 72] PSIG, in which case you'd need to decide if the error is acceptable or if some tweaking is required.