So you are saying the Coal Trol users can idle down even more? Your timer box has has the room sensor that extends 25 ft and is upstairs? Kind of confusing but I'm learning. Feed rates,etc. all Greek to me. Once I get the stove in and up and running I'll learn fast. Sink or swim.
Where my timer control box only has an off / on for the fans and feed motor, I believe the coaltrol has some ramp up/down speed capabilities in their settings. I have not used one myself so you would have to read through their threads to be sure. It seems this would provide more accurate feed / temp control than the simple on/off my timer box has. Somebody here put a coaltrol on their harman stoker and was very happy with the performance compared to the timer box - can't remember who it was offhand.
I have my thermostat upstairs and the wires run down to the timer box on the stoker. There was some trial and error on the thermostat setting and timer settings when I first put it in to get to where I am now happy with it and leave it alone. I wasn't far off with the initial settings, but played with the thermostat setting and air circulation issues to get it so the room where the basement steps are located doesn't get to 75 while the rest of the house is 65. The timers were tweaked until I was getting the coal burned up before pushing off the grate but wasn't burning back into the hopper and wasn't firing too often.
Similar to your situation...the guy I get my coal from switched over to a used harman stoker from his hand fed harman about a month ago. He had tried it earlier in the winter but couldn't get it to put out any heat (side temps about 300) and wasn't familiar enough with it to know what to tweak. The guy he bought it from insisted it burned at those low temps for him from the day he bought it new (he never adjusted anything after it was installed for him), but he had it in his living room so maybe he didn't need much heat output. We discussed it when I was picking up some coal and he eventually got around to trying it again. I think the main thing he did was adjust the feed rate rod about 6 turns to feed more coal which is quite an adjustment. It heats up normally now and he is real happy he switched and wonders why he didn't do it years ago. This is a guy who sells coal for a living and in the middle of his frustration with the stoker was starting to wonder why he was selling so much rice coal if these stinkin' stokers couldn't put out the heat.
I guess my point is to expect to do some experimenting to get it dialed in and working for you per your house layout and chimney draft.