My answer to your question is pretty much the same.. Just look at the times when you would want less heat, afternoon with the sun out.. you wouldn't just turn off the fan,, you would also turn in the air control as well.. I can't see a scenario where you wanted enough heat to possibly damage the stove, and not have the blower on. They kind of work together..
Once you get the stove installed and use it for a few weeks or at least through several weather changes, you will get 'a feel' for the best settings, and when you want to use the fan or not..
Since you have a Harman, they are really overbuilt...I wouldn't be concerned with damaging the stove.. The one Harman that had a bad baffle, and cracks on the sidewalls where the baffle was welded in, that was the subject of a discussion on the forum.. It was pretty old, 20 years sticks in my mind, and the stove had burn a lot of wood,, which can be a lot hotter than coal if not controled..
What I mean is that a good load of wood in a stove, and the door left open will turn the stove cherry red faster than a load of coal with the door left open.. I have personal experience with a cherry red wood stove.. it only took about 20-25 minutes,, and it was a much bigger, heavier stove than a Mark II or III.
The Harmans are built like tanks.. I wouldn't be concerned..