My result has been shorter burn times, more wood consumption and less coal and more powdery ash.
^^^ None of this is a good thing. Also running on one month's experience, I have found my best results to be raking as much of the coal bed into the center, directly over the slot. Actually piling coals in the middle, along with any unburned or partially burned pieces. Any new wood goes on the sides and top. The results seem to be that, once the blower kicks on, it lights the coals over the slot immediately, and will draw air from the sides right through the coal pile. I get instant gasification, no smoke.
If there's still a full load of wood in there, I don't touch it, I just add some more. I get a full 12-hour burn or more out of a load of wood, and most of the time I load so the top of the pile is level with, or just above, the bottom of the door. This past Sunday I loaded it at about 10 am and did not touch it again until 6:30 on Monday morning, and it was down to a full bed of coals and still hot.