Run a few electrodes and have someone monitor the voltmeter to see what voltage range is reasonable. Just because one can hold a long arc, doesn't mean the weld is going to be acceptable. The ranges should be reasonable and should be capable of depositing an acceptable weld. Different electrode classifications - different voltage range. Different electrode diameters - different voltage ranges. Different welding position - not too much difference in voltage for a give electrode classification or for different diameters.
The WPS you submit to a customer is one way they assess your level of technical expertise. If the values you list in the WPS are unreasonable, an opinion is formed.
I reviewed a WPS that was qualified to ASME Section IX. It listed the voltage as 0 - 220 and the amperage 0-350. You can imagine the opinion that formed as soon as I reviewed the WPS. "Here is an idiot that knows nothing about welding."
I usually get three or four calls a year from people that ask: "Where do I find the voltage, amperage, and travel speed to list on the PQR?" Opinion: "Here's another idiot."
We all have to learn from the school of hard knocks, going to college, reading books, or having someone that is willing to mentor us. That being said, the opinions I form now are tempered by age and recognizing the fact that none of us were born with the knowledge needed to be all things to all people. We all have to take our lumps, bumps, and falls. That's how we learn. Learning is a slow, painful, and expensive process.
You will never learn to swim if you don't jump in and get wet. The same is true with learning to write a WPS or learning to weld. In the case of welding; just try to say on dry ground while doing it or you might find it a shocking experience. At least, that's what a few welder/divers have told me.
I hate to say this, but just because someone holds a CWI certificate in their wallet does not mean they know squat about writing or reviewing a WPS. You wouldn't ask a 16 year old kid with a brand new driver's license how to prepare for the Indy 500 (unless you are a 14 year old). You need to develop an association with someone that knows the ropes. I recommend you seek the services of a SCWI. The SCWI examination is intended to verify the individual understands the rudiments of writing a WPS and how to qualify the WPS. There is nothing on the CWI examination or the CWI seminars that ensures anymore than the individual knows where to find a bit of information on the form. Learning how to write a WPS comes much later.
Best regards - Al