Finished my brew day. It was the first use of my Captain Crush. It would appear there is a bit of a learning curve.
I have no first hand experience with other mills, so I can't say if my problems would have happened with an MM3 as well. I ran into some trouble experimenting with the gap. Since I'm doing BIAB, I tried setting the gaps a little tighter than the recommended starting point. This worked for a few seconds, but then the lower roller would stop rolling and get stuck full of material. It was very frustrating for a while there. I began experimenting with different settings until I got it to work. The bad news is I didn't get much time to play with different settings to get it fine tuned. The good news is that it sucked that grain down in just a few seconds! Once I got things set right it devoured about 10 lbs of grain in less than 30 seconds. I was using a 3/8" Dewalt corded drill. My poor drill was working about as hard as it could to roll that grain through.
I did get pretty poor efficiency despite running it through the mill twice. I've gotten just over 70% with the crush from the LHBS's mill set at 30. I got around 60% today.
So, I'd love some advice from others with a three roller mill like the MM3. Is it finicky about that third roller if you crush too fine? If I can figure out how to get it dialed in, I'm going to love this mill. It's way more sturdy than you would think. If I continue to have to grind too coarse to get it to work, I'll be bummed.