I will water slake plenty (although I usually prefer to use pulverised for that since it I can avoid screening.) However, I have read other recipes involving air slaked lime for stucco. Millar mentions three distinct methods for slaking limes:(1) sprinkling with water, (2) immersion in water, and (3) allowing the lime to absorb the moisture of the atmosphere. I have never done nor do I have any knowledge of 1 or 3, hence that is why I would do as I said.