Coal burning in a Consolidated Dutchwest Sequioa stove

This stove is 10-12 yrs old, it can burn coal, but I have never done it until now. It has an underfire draft adjustment, an overfire air adjustment and a draft adjustment on the very top part of the stove that goes to the flue. I can get a good coal fire going, using wood and then adding the coal. I then add more coal and all goes well. If I want to cut down on the heat output, I assume I can close back on the air adjustments. I have played with them and I end up with the fire going out due (I guess) to not enough air/draft. So, my question is how soon after making an air adjustment shoud I see/feel a difference in temp or flame? And what air should I be adjusting? I suspect that I am making too much of an adjustment, and it kills the fire. Is there any place on the web where I can see photos of a coal fire and how it should look?
Thanks

ohiorick wrote: It has an underfire draft adjustment,

When you start it open that all the way, once the coal get going you can close it all but a little bit. Adjust as needed for to burn the coal hotter.

an overfire air adjustment

Really not sure what the usefulness of these are but have seen them on many old stoves. It would probably work well if you have overfired the coal and it's very hot. you could open this allowing air into the unit but it won't fire the coal up. For the most part leave it completely closed, on a side note my aunt has been burning coal in a hand fired stove for over 40 years and I have yet to see this open on her stove.

and a draft adjustment on the very top part of the stove that goes to the flue.

What that does is resrtict the air going out the flue. It holds the heat in the stove. Most of my customers add an additional damper like this right on the exhaust pipe. When starting the coal leave it wide open, once the coal is sufficiently burning you can close it almost fully. Open it up before opening the door to add coal, this will allow for any gases built up in the unit to escape.