You said it yourself, the pork butt is what you want. It is just the right size. Boston butt, pork butt, it can be labeled with many names. Honestly, i am not even sure I like the whole shoulder all that much anyways. Are you using charcoal, electric or gas. Best of luck to you, and awesome you are giving it a go. I have taken them frozen and gas grilled them in a couple hours and they are decent so have some fun and no worries. I like 2 to 1 sugar to salt rubs, but some prefer more salt and spice. 200° is a good starting place. Give it a little trim too for better results.