Lack of smoke in lbge

If you followed Stike's graphic of a cross section of the firebox with wood mixed in the column of lump roughly the size of the diameter of the bottom, you should be cool.  Even if you don't add any wood, you still get a smokey taste from the lump.

Smoke in a low-n-slow is most visible when you're cooking off the water in the wood or if the wood is green - you see water vapor (white steam) and more combustion particulates (grey).  Most of the tasty chemicals in smoke are nearly invisible.  So if ya can't see smoke, it don't mean there ain't none.  How'd it taste? 

Don't worry so much about how the smoke looks as much as how it smells.