They're great aren't they? I adjust my dial pretty much the same as you. Its been running flawlessly since Friday.
I never used rice coal but I've tried Pea, which in my location is a size under nut. The pea coal seems to lay up nicer and from what I'm told it is supposed to give you a longer burn due to less air gaps from the tighter fitting coal. I haven't used enough of the pea and I've been using nut size since I put a ton in my basement. It burns great. I get consistent results with it.
I can't say enough good things about the stove but I live in an large, old house that has some pretty bad windows upstairs and I think I need a larger size stove. Its getting colder and I'm really asking too much from the stove to heat 2,800 sqf. So, I'm in the market for another stove, maybe a Harman Mark III.
If anyone here has familiarity with the following brands of hand fed stoves let me know about them please: Baker, Alaska Kodiak (Hand Fed), Surdiac, Hearthmate or any other unit that they can recommend or describe problems with, I'd be appreciative.