"This is the second piece I have read that mentions the critical nature of the burner-pan distance in producing CO..."

Anything that gets in the way of complete burning apparently contributes to CO. Sterno says their product doesn't produce CO, but some studies have shown that a wind screen or other barrier around the base will raise CO to dangerous levels.

So, does that mean that if you are burning Sterno in your tent and don't have any air barrier around it (you wouldn't need it), that it burns cleaner? It sounds like that...

Sue