I did the "add wood" early on in my smoking ignorance. I used a total of 12 to 14 ounces of wood, not knowing or caring what each piece weighed having assumed they were in the 1 to 2 ounce category. Ruined a butt. Even the dog would not eat any of it. So, I weigh the wood, get the smoker going, and never add more. Ever! Meat is too expensive and after drooling all day anticipating good food, it is very disheartening to have to head out to the golden arches.
As for placement, I have tried different locations and yes, I have noticed some difference in length of smoke, but not so much as to be a plus in flavor.
As for drippings and such, I always start with a fresh lining of foil over the floor pan and the wood box. And use a plastic putty knife to get what ran under the floor foil. All in all, good food and minimal maintenance.