Scaling is similar to the straight or sidewinder versions. Remember, the original development model wasn't even a 6" but a 5" instead. I know of one that's an 8"
workshop heater and it puts out a lot of power.
How to scale: take the published table and size the firebox and port accordingly. The short riser behind it
should be the same size as the table suggest but the height isn't higher than the firebox top. The top box is as deep as the firebox and riser together, and a square cross section, as wide as the firebox. The stumbler halfway of the top box' ceiling, roughly as high as the port is wide. The end port 75% of the round riser's cross section, as wide as the top box and posioned about a quarter of the top box length, measured from the front.
Is this sufficient information?
And oh yes, in early July I participated in an
art project equipped with an 8" version in Belgium. The bare core was run with just one meter of large stove pipe on top to act as the chimney. It ran beautifully, despite being completed that same day and still soaking wet. Within ten minutes the smoke disappeared completely, producing the right sound and all.