I would get on a regular schedule of filling and shaking down the stove. If you search in the hard fired section you'll find everything you need to know but let's say you are filling and shaking twice a day at 7am amd 7 pm. About 15-30 min before touching it, open the MPD and open the primary vents on the ash pit door all the way. This gets the fire reved up a bit and helps lower the recovery time of adding fresh coal.
After this time period, do any poking of corners or center of pile etc.. then add your fresh coal, and then shake the stove till you get a nice glow from above into the ash pan. L
Leave the stove wide open as it was for another 15-30 min or till you know it's caught (blue flames)and rising temps then close your MPD all the way or at least 45° and set the primary dampers for the heat output you want. Rinse and repeat in 12 hrs.
Looks like your loading door has secondary dampers also and those are also opened for a while after loading fresh to help burn off the gasses. Again about 30 min or so till you see blue flames.
So yes, more air on the ash pit door primary dampers equals more heat. The MPD is open to Start/Shake/ Fill/ then closed down after the 30 min after filling and burning off the gasses. Hope that was helpful.