The question is now, if you're trying to get more smoke flavor into your foods, should you try the opposite vent settings? Put your smoke wood on, let the billowy stuff burn off, then add food. My thinking is that the longer the smoke is in contact with food, the smokier it will be. Top vent open pulls the smoke thru much more quickly than the opposite. I get the thin blue smoke either way, it just depends on how smokey you want your food. This may all be painfully obvious, but you've at least proven your chunks don't just evaporate.
Robert