Jay: I do not do big blocks of cheese. I break all of mine down into snack size pieces. That 4 pound block would make 8 sticks the way I do cheese. I have a 6" and a 12" tube. In the 066 I get a little over 4 hours of smoke, and the 12" gets around 7 hours of smoke. When I do harder cheese like chedder, I go with the long tube, and use the short tube for softer cheese like Havarti or Guda. You are right about having a hard time keeping the tube lit in the 066. I pull the wood box out, and place the tube right over the lower drain/vent hole. You need to get a good burn going on the tube before you put it in the smoker, or it will go out. I bought a wood clamp that is long enough to go over the top of the smoker and it holds the door slightly ajar while using the tube. I place a big pan of ice on the bottom rack and position it right over the tube. I turn my cheese every hour or so so that I get smoke on all 4 sides. When the cheese comes out of the smoker and cools down to room temp. I put it in a zip lock and into the fridge for several days. This seems to get a better smoke flavor deeper into the cheese.