The amount of wood you use depends not only on personal taste, but also on the surface area of the meat compared to it's volume. Ribs have a large surface area per unit volume. Pork butt has a small surface area per unit volume. For ribs I use about 2 to 3 ounces of wood no matter how many racks I'm doing. For pork butt I use 4 to 5 ounces no matter how many butts I'm doing. Some use up to 8 ounces on a pork butt because it's almost impossible to get too much smoke on a butt. Also, here's where the personal taste thing comes in. The amount of wood you use will ultimately have to be a function of your own personal preference along with that of your family and guests. There's no need to add more wood that only causes you to open the door and lose heat and smoke. Just set it, forget it and enjoy an adult beverage or three.