I burn lump too. Sometimes straight RO, especially in the mini basket. For long cooks I go with mostly Lazarri with some RO mixed in. I'm guessing 10 pounds average. I have tried briquettes only once or twice, there was too much ash and I just like the flavor the mesquite lump gives me.
Pat, If you shake the cooker you you run the risk of a plumb of ash that will rise, following the natural draft and stick to your food. Try making yourself a wiggle rod, you can see my BDS size one in the picture. It's just a 1/4" rod with an L shaped bend on one end. Sneak it into one of the lower vents and gently shake the basket