I use a standard Weber smoke box (you can do almost the same thing with chips in aluminum foil), but I supplement it with an
AMNPS tray that I put down in the grease trap. I put it in the trap because if you put the tube or tray up in the grate area, it is way too hot up there and the pellets in the
AMNPS tend to burn rather than smoulder.
Remember that there is a LOT more air going through most grills than what goes through most smokers, so you need to generate a lot more smoke to get the same effect.
Here is the thread I started where I showed how I use the
AMNPS in my Weber Genesis:
Rotisserie Smoked Chicken - Using All My Toys At Once