I live in Alberta and used to live in Grande Prairie and Slave Lake. I don't guide but have shot lots of Wolves. Spot and stalk hunting for wolves will have about a zero success factor. Sitting and calling for wolves, if the caller is real good, is about 20%. The only sure way to take wolf is over bait.
If you want to find a good wolf guide the relevant questions are, how many baits does he have out, how many are actively being hit, how far apart does he have baits spread out. If it isn't at least 400 Klms in circumference from his base of operations he isn't hunting a big enough territory. Does he have blinds set up, are they heated. Dec, Jan and Feb the temp can easily get to -40F, without a heated blind, even at -10F, most guys will never be able to stay out long enough to last dawn to dusk, You can't night hunt in Alberta.
Ask him what his success rate was the last couple of years, anything 50% or better on a 7-10 day hunt is a great guide. Make sure you talk to some clients who were unsuccessful as well as ones who bagged a wolf. A wolf is smart and learns quickly. They are hard to take, which is what makes them a great trophy.