I am going to bump this, even though the OP gave up on it long ago. I just purchased this and will assemble tomorrow, and will report back with results. But several faults, a few pointed out, a few not when it comes to this set up and smoking in general. This is a "Texas Offset", which means unless you are "grilling" a few kabobs in the "smoke box" ... it's made for more wood or lump charcoal.
but ok, until I prove otherwise, here are a few things I see wrong with the OP and a few other people's posts on this:
1. Mods right away. We all want to have our own "I did it my way" rig. But out of the box this particular model is flimsy, design is lost to give it more sq inches of grilling/smoking space. On top of that it is a flimsy metal design. For $120 more today I could have got the Trailmaster, which is a heavy duty design you want, but for that much more you lose 100 sq inches, plus the "above rack". Which to me, in a "hybrid" grill/smoker, is a necessity. So it IS a lower end model. Learn your rig, what it's faults and strengths are, then mod accordingly/ to your liking.
2. Smoking is an imperfect science, if you want a "Set it and forget it" rig, get a pellet smoker. Those are true Ronco style Set it and Forget it rigs. So why are you using 3
charcoal chimney's worth of fire? If you are using Charcoal only, briquettes, chimney should only be used on the initial starting of the fire, OR in unattended emergency situations to beef the fire back up. Otherwise you are LOSING not only the SMOKE you are wanting, but the burning time per briquette. After using the Brinkman Smoke'n'Grill for a year now, the R2D2 looking unit, my biggest problem with that is that the stock thermometer does not read exact temps and overall it's too small, especially the door to keep putting in wood chips and charcoal, otherwise that little thing cooks up some good food. And if the OP is still paying attention, did you add any type of water box? The water absorbs the smoke flavor and heat to even the temp out through the smoker.
3. Patience is key in smoking and "mastering your rig" ... Yes before I bought this rig, I knew it's faults. Grill like top, offset smoke box, flimsier than I would like metal. Will I make mods? Maybe, but the point of this rig is to be a Grill And Smoker! The OP and another poster said they hit the dreaded 140 dg mark and stalled out, Did you all wrap your ribs or shoulders in aluminum foil? The general consensus on how much smoke a meat can absorb is between 2 to 3 hrs worth, then it's keeping a steady temp to help break down the soft tissues. 140 is the point where you wrap it, ribs, butts, shoulders, etc. Chicken in my own account, and this is my Own account, does not do well with an R2D2 style smoker, for the simple fact it will "leather" versus crisp the skins. But I might not have left it on long enough to crisp. Once again Patience.
4. Other than shoulders, which sometimes can use this, you still have to put fire to your ribs, you have to, to set the sauce, to set the rub, or whatever. even if its just a minute or two. Offset smoking will not char your ribs alone. Smoke ring and tenderness, check, a little char and "cooked" look, set it to the flame for a few minutes, and bammo.
That's my 2 cents for now, will report back after I set it up and see how it goes.