Sounds interesting... I'll definitely be following your experiment.
Learning generally boils down to "Repetition or the avoidance of pain", some people learn by doing, some by watching and some just have to pee on the electric fence.
Whether you think that you can, or that you can't, you are usually right. Henry Ford
You should be able to make it work but it'll take some trial and error to figure out the intake adjustments to maintain correct temps. I remember a few years ago there was a guy that built a gravity feed chute that he could connect to the top of his FB and burn charcoal so he could get some rest. He said that it worked great once he got it dialed in but it burned a good bit of charcoal to maintain temp.
From my understanding, the depth really doesn’t matter much. Obviously, the deeper it is, the more charcoal will burn at a given time and the more heat you get. I would make it deeper than you think you need as you can experiment with fill level. Biggest issue I have seen is the lit charcoal “jumping” the maze and starting a runaway fire.
I ran a tradional offset for years and had great luck with the minion method. You simply fill a basket with unlit charcoal and then dump a single lit chimney on top. The idea is the top burns and lights the layer below and it burns to the bottom of the basket. Seems like it would never work but I got 4-5 hours of consistent heat from it without touching g a single vent.
My smoker was a bunch smaller but you might try it before you go to the extra hassle of a maze.
You may have to experiment with which end to light as well. In my tube smoker I built a 3' long charcoal basket to begin with. Doing as Dirtytires suggested I lit the top of the coals. My fresh air intake is low center and the coals would burn in a V pattern with the center burning hottest and working it's way to the ends. When I had an air flow issue in one side the fire traveled towards the hot side of the fire box and left the other half of the coal basket unburned.
I did get up to 7 hours of burn time with 12# of charcoal although my overall cc/fb are smaller than yours.
It’s a Science project really since there’s so many parameters that go into figuring it out. If it was just a vertical there would be some folks that have some experience. If it was me I would build it the full size of the fire rack and half the distance from where the fire rack sits to the throat bottom. This would allow for a good bit of charcoal and air supply. When Gizmo did something similar he used an guru to control the air flow. You may have to make an opening or fitting for that across from the throat opening so it could move air right across the maze. Because of the side walls of the maze the normal air intakes may not feed the air sufficiently. But you could cap that intake when not in use.
jm2cw
Making memories!
Current Smokers: Backyard RF Offset and Hybrid RF Offset trailer rig with Cowboy cooker and fish fryer, always room for more........