Nozzle-tip-circle = common circle for the tips.
Unevitably enlarging asks for a greater chamber diameter…
Narrowing the tip-circle diameter would increase the imaginary
“downdraft” over ~0,61m/s, which has seldom given good
results. (In 2-throat gasifiers)
Bigger fuel bits “mature” slower, so a slower imaginary downdraft is required… toward 0,5m/s is recommended minimum.
In a built measure, only a conical roof can hasten the process… TomC mess. 635.
Blowing 15 degrees upward from the horizontal plane would also increase preparation time…
Same nozzles, but the “tip-bore” 15* aimed upward, slightly off hearth centerline to generate a bit of rotation.