I've built a small TLUD from a 4 gallon stock pot, and a 1 gallon tin can.
I fill it to almost an inch of the lid , douse the top with accelerant and light.
When I'm sure its lit, I cover it with the lid/chimney.
It burns about 45 mins, or an hour, I think, its been a while.
Lately I have only made char in the bonfire.
An old steel tool box stuffed with bones, bread, willow, cardboard, etc, goes in the bottom of the pit.
The willow turned out well, I hoping to monetize that in the future.
Bryant, does your setup continue to burn once the chimney gasses are lit?
The trough style has the advantage that you could add to it as the material reduces.
If you put a lid on that, you lose that feature.
I can see wanting a lid to starve the coals of air at the end of a burn but not otherwise.
I'm building a batch rocket powered black oven.
It occurs to me that it could make a fine biochar kiln.
One would want to burn off the gasses produced.
If you build it as white oven, you could re-route the gas produced into the rocket itself, for a self perpetuating process.
I wouldn't do this with a black oven, as the pyrolysis gasses would be mixed with the finished rocket exhaust, probably not a good mix.