If doing one huge one or two butts in a kettle, I'd use a disposable pan and do a hi-heat (275-325) cook with all Kingsford briquettes to one side. Cover with foil at 160 or 170 internal meat temp, or if the bark turns black.
If you have a Weber rapid fire charcoal chimney, do this: Fill the chimney 3/4 full. Pour the unlit charcoal on one side, banking in a slight slope against one side of the kettle. Lay one wood chunk in the middle of the briquettes. Take some aluminum foil and cover the other side of the charcoal grate that'll be under the meat. Light half a chimney's worth of charcoal and when it's ashed over at the top, pour on top of the unlit, taking tongs to re-slope and push toward side of kettle, and then put one more wood chunk on top. Put the cooking grate and lid on, but don't put the meat on until the smoke looks clean enough.
BTW, this is pretty close to G. Wiviott's method as outlined in his "Low and Slow" book which you can probably find in a bookstore. I'd just ignore his insistance on using lump. Briquettes will last a good bit longer. Also, one other thing: Try to make sure your lid's not out of round. If it is, you'll have a harder time keeping temp under control.
To check temp, hang a clip on therm in the top vent, and place that side of the lid opposite the coals. (Replace wood chunks as necessary, simply laying on top of coals.) Adjust temp with bottom vents only, noting that temps are much more responsive to opening vents, than closing vents if temps are too high. If you have trouble keeping it under 325, you'll just end up covering the meat with foil sooner. When temps start to plunge and the vents are open all the way, that means it's time to add about 1/2 a chimney's worth of LIT charcoal on top of another wood chunk. If the smoke's billowing, wait a little bit before replacing the lid.
