Have him limit the amount of secondary air (over the fire air) as much as possible after burn off of volatiles of a fresh load.
Make sure the load door is sealing completely by doing the dollar bill test. Close a dollar bill in the door seal and see if it pulls thru without much effort.
Make sure all primary combustion air is coming in under the grate and can't be routed around the coal bed. I'm not sure if this particular fire box has air passages for routing primary air up over the fire. Routing of primary air up over the fire will hinder heat production and cause heat output to drop prematurely thru the burn cycle and lead to a dead fire.
If the above guidelines are used, it WILL produce a hot coal fire UNLESS drafting is inadequate. Draft needs measured with a manometer to determine.
Excellent post J F Graham..