We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:
If you have a tall burning chamber and have a foot of headroom above the firepot, secondary combustion will take place there. Air can be injected into that region, but it will take a bit of experimentation.
Don't re-invent the wheel - use a Riello or Danfoss control box, suitably modified.