No one's chimed in on this so I'll give it a go. I've only played with the EM0480 and the compak k3 doserless and they all clump. I'm guessing most doserless will clump to some extent due to static build up, and where a doser will unclump a doserless will grind static and all into the portafilter. I know mazzer has a anti-static mesh that is fixed at the grind exit which helps with that. Not sure you can do more than what you are doing unless you find a way to get rid of static prior to the exit chute.