I agree with my esteemed colleague, but allow me to amplify a bit
Originally Posted by BBQ Grail
Just my opinion...
Rub: Yardbird Rub - If you don't have any there are several good recipes for rubs on the forum. There is a Google search box at the bottom of the page that searches only this site.
Cooking time: Until it's done - at 225, plan on 90 minutes per pound, but that is just a guideline. It is done when your probe goes in like it is going into warm butter. This may be at 185 or not until 205 internal temp. Allow yourself plenty of time. You can hold it in a dry wooler with clean newspaper or towels for insulation for hours.
Temp: 225 degrees - This is a good starting point, but butts are very forgiving so don't panic if the temp goes higher. Of course, the cook time will be shorter at lower temps.
No Foil - unless you need to speed up the cook. Then you can foil with some apple juice and it will finish faster.
Leave the fat cap on and down - Trim off any hard fat and any areas that are very thick, otherwise i agree.