I rebuilt my lid. It now does not leak. Very nice! I had used a silicon rope material for the seal that was not nearly pliable enough to conform and make a seal. I replaced it, and rebuilt the lip it rides on.
Went ahead and tried another run today. I broke up my charcoal into bits about thumb size. I did find quite a bit of the bigger charcoal chunks in my bagged charcoal were not fully converted. More like charred wood then charcoal. I put the still-wood bits above the level of my jets in the hopper.
I played with it for about 50 minutes. Still didn't get any flareable gas, unfortunately. Lots of white smoke for the first 10 minutes or so, then it became more wispy. I smell like a smokehouse. Makes me want some BBQ!
I suspect that I may not be pulling enough CFM through to get proper conversion? The blower is one of the only places I've deviated from BenP's design, due to lack of availability. I do have a pitot tube and can figure my blower CFM - anyone have a rough idea what I'm shooting for?
Back of a napkin guess: Sine this is sized for a 4 liter, and we'll assume it can sustain a fast idle at 1100 RPM
(1100 RPM) * (1 intake stroke / 2 revolutions) (4 liters displacement) = 2200 LPM =~ 75 CFM?
I also suspect that trying to ignite the gas coming out the end of a pipe is probably not the best burner design... But it does seem to work in video's I've seen?
My other thought is perhaps my char bed needs to be even finer grained. Not sure at what point it will clog, though.
I'll keep playing with it. Next time, I'll take pictures of my feedstock before I burn it. I'm learning that Mr. Keiths assertion of woogas being 75% operator rings true.