I’ve used pink noise in an Audioscan Axiom test box to verify noise reduction features in some devices. With the Intents, I will notice the most obvious changes when adjusting the NNS-Difficult amounts if I am using a 90 dB noise signal. As of this writing, I have not found a testing parameter i.e. input level to evoke obvious changes with NNS-Easy adjustments.
Note, this is leaving the rest of the MoreSound Intelligence parameters alone, like Virtual Outer Ear and Sound Enhancer.
As far as time between measurements to get the largest measurement, I think 15 seconds is fine. That is, I would not expect you to need to take more time than that.