ddahlgren wrote: My big goal is an overnight burn with a peak of 40k btu / hr and a low around 5k.
That's not going to happen easily. Coal is very slow responding, so most set the stove for a steady output for 24 hours and vary that as the season progresses from cold to colder and vice versa.
You are looking at features and might find a stove with all that you might want and it turns out to be a dog because the features are badly implemented.
A tall round stove means an antique and a good one is probably more money than you want to spend.
A good stove has to start with a strong effective grate shaker system without which there will be nothing but frustration trying to maintain a fire. The shaker system goes a long way in providing satisfaction to users of Harman, Hitzer, DS Machine, and other higher ranked stoves.
A round lined combustion chamber is best but the square and somewhat rectangular chambers can do well also.
Stay away from pot belly or cannon stoves as they are not airtight and are very hard to control. Use the search function in this forum to find threads on prospective stoves you might be interested in.
Stoves with thermostat will compensate for changes in draft and with a hopper is well worth having.