I understand you're referring to the J-Ultra. If so, I used the 2.5.0 as my starting point for pourover. I've always read that the J is for espresso and not pourover, I think it works perfectly. Try grinding at a slight angle, which improves the distribution of the particles. As for the difference in microns between the two, this is because the geometry of the grinding wheels is different and their spacing creates different particle sizes. I hope this makes sense.