a better/or completely different chamber design for flue curing?
Of course. There is always a better design. When home tobacco growers first attempted flue-curing, we looked at the massive, industrial flue-cure chambers, and considered how to duplicate the process at a home scale. My first experiment was what came to be known as the
Cozy Can. It works, but is not really large enough to be practical. The Cozy Can's greatest value was in exploring the essential requirements for successfully flue-curing a small batch of green leaf, and it's worth reading, just for the concepts.
My endoskeletal kiln was designed specifically as a larger capacity
kiln, to replace a converted, wooden toolbox that I had been using as a kiln (not flue-curing). The question of whether or not the endoskeletal kiln (specifically the XPS foam and the Tyvek tape) would withstand flue-cure temperatures was an open question, until I gathered the courage to attempt it—at the risk of destroying my kiln. It worked, and the materials of concern seem no worse for the wear.
That was the end of my journey of kiln and flue-cure chamber designing. It works for me, and that's what I use. Any member of this forum (and maybe their teenage kids) could certainly come up with improvements and re-designs. My goal was simplicity. I'm sure there are other and better approaches out there.
Bob