I looked at this and was VERY impressed with the volume of quality charcoal he produced.
What if you flip the process on its side and do it like a coke battery. In coke production some of the gas produced is burned, some it sent to recover chemicals, and some of it is cleaned and used like producer gas itself in the steel mill for process heat.
I see no reason why staged Charcoal battery could not produce more charcoal, more efficiently by copying the technology already in use for over 100 years in Coke production. The trick is the staging… Each cell in the battery move through a cycle where the adjacent cells provide heat at the beginning of the charge, then the cell produces heat and fuel gas as it finishes the product. Its a continues rather than batch process.