I recently purchased an AMNS. I was very impressed with it but had one problem. I have the 6x6 unit. I loaded it up with apple dust to smoke some chicken in my cheapo gas grill. When I opened it up about an hour into cooking, the whole thing was burning. All the dust, meaning it wasn't continuing on it's nice path. Now, I was cooking around 250 degrees. I know the paper that came with it said for temps over 180 to keep the middle row empty of dust. But my question is this: if I leave the middle row empty, want it just die out when it gets to the middle? Or do I need to light it at both ends? Or just re-light the other side after the first side burns out? Thanks for any help.