Redneck, I am in no way trying to step on your toes, but I can't help but to wonder if the fire below like you describe. Could cause fumes to build up near the top of the drum and cause it to make a big WOOOFFFFF!!
Its just a thought i had, cause if something like that can happen then it will do it to me.
I do know that I had a 42 inch long piece of 3/8 pipe, open both ends, and stood it on 3 bricks. Loaded it with leaves and lit the bottom.
OMG let me tell ya, it looked like the tail end of a jet turbine. I had flames 20 to 30 feet high burning the branch's off the neighbors cypress tree. Almost had to clean my shorts after that one.
As far as the drum, maybe a good decreasing could take some of the hazard out of the burn.
Try to keep us up to date with build pics, only thing better then a good build is good food.
But we like um both.