My birds played with/threw the superfine Harrison's pellets and wouldn't touch the fine size. The coffee grinder made it all powdered and they didn't like that either. I finally used a regular old handcrank nut grinder to crush the fine pellets. It leaves some chunks and some powdered. This is the only way I have gotten them to eat it. They love it now. I also have it in a seperate dish from the seeds. They are really good about eating both plus the veggies.
Basically, it is a lot of trial and error. You just have to try the different ways because each flock is different.