Problem with the tube smoker is there is no where to place it where it will get air flow. I've tried and found it just doesn't work well, but running pellets and or wood chips against the chamber (See Tommy Ring ) will get you smoke going pretty good.
BUT...... Even with a heavy smoke rolling you may still not get the desired amount of smoke you want or need.
The hottest part of the SRG chamber is at 5 o'clock position. That's just right of the controls if looking at the front or if you have the newer SRG it's where or close the where the smoker box is built into the side.
IF..... A heavy smoke is your thing, plumbing is a smoke generator from the side going up into the chamber may be what your looking for. I have done this on TBE and work well. Others here have done this as well so nothing new to learn, just good solid advice
BTW, Todd at A-Maze-N smokers and I worked on the perfect smoker for this unit and I own one problem is cost and it would be half as much as the SRG was to buy so he backed off for now