Irish1, Welcome to SMF. Start out with your shoulder right on the smoke rack. Your shoulder will get the full benefit of the smoke. When the shoulder reaches 165*, it will hit the temp. plateau; it's at this stage that we normally wrap the shoulder in aluminum foil. You can put the shoulder in an aluminum foil pan and cover it with foil wrap and put it back into the smoker. When the shoulder reaches 190-200 degress, wrap the aluminum pan in some old towels and place it in a blanket lined cooler for a couple of hours (Don't worry, that shoulder will stay hot). When your ready, it should for the most part fall off the bone, except for one section which will require some chopping. Oh, and don't forget SoFlaQue's Finishing Sauce-a must have with shoulder or butts.
Enjoy!