I have gone both ways. In my smoker,, if straight on the rack,, you do not get any drippings like you would get with a foil pan. Smoking,, doesnt make a difference in flavor or texture except for juices,, the temp will be lower but will slowly level out, only because of reflective nature of the foil pan. Once inside of smoker is up too temp,, makes no difference at all,, IMO. If you are young and not afraid of melted fat,, those drippings mixed with some bbq sauce,, what a cocktail too dribble over a sandwhich :),, but without, pork is juicey enough to stand on its own.
Remember there may be a stall in cooking,, allow for it. My average cook time with 8# on electric MES is 16 hours at 225f. That normally gives me an internal temp of 198f which after it sits for an hour, wrapped in foil - towel in cooler. It comes out perfectly.
Trust me,, I understand your feelings of intimidation. I am a computer geek,, smoking something too me was so far out of my league,, crazy. Simple steps too follow and you will do just fine.
1) Not sure what you have for a smoker but make sure temp guage is accurate. If you can get something with a probe too put in the butts,, even better. When they hit internal temp of 195 - 210,, they are done,, let them rest.
2) PLEASE,PLEASE,, PRETTY PLEASE with SUGAR on it, let it rest. The juices when you cook,, settle to bottom of the meat. When it is at desired internal temp,, pull it,, wrap in foil,, wrap a big towel around it and put in a cooler. As the internal temp cools, the meat will suck the juices back up inside itself. Let it rest as long as you can. I have done up too 3 hours and it is so hot n juicy that you will burn your hands trying to pull it.
3) Your perfect flavor is going to take you a long time to develop and work out. Dont be concerned right now. Pretty much any recepies that you see here on the site for pulled pork ? The pork flavor is the king. Rubs give the outer crusty layer extra flavor for those of us that like those chewier bits,, inside ? Sweet juicy pork :)
Hope all goes well,, Happy Birthday to your son. If it doesnt turn out like you planned,, promise him a special cookout between guys,, then fire up the smoker and make him something extra special :)