I've done quite a few pork butts in mine a lot of different ways and I don't know if much extra "monkey business" is worth it . I guess I just like to rub some mustard (prepared yellow mustard like on a hot dog or hamburger ) then sprinkle some rub on it and put it in the smoker . I have done this the night before and I have also injected them with juice etc. , and then sprayed them as they smoked or mopped 'em with this or that and I really can't say I prefer one way or the other . One thing I have been doing with beef and pork , I let it sit at room temperature for an hour or 2 , I just keep it wrapped or covered with plastic wrap . I wouldn't ever do it with poultry and I don't think anyone else would either , but I've been doing it with pork and beef now for about a year . Let it set at room temp and then put it in the smoker . I guess if it was 90 degrees in my house maybe I'd only let it set for 30 minutes or so .
The one thing I have discovered is when doing a chicken or turkey or just parts of them , I'm going to stick with brining them . I did a chicken a while back and I thought I'm not going to monkey with this one , I just put some rub on it and smoked it but it really lacked flavor and did get a little bit dried out , so I thought from here on out I'm going to stick with brining poultry .
As far as working with the pork , I guess if you want to spray it go ahead and try it that way . You'll probably lengthen the cooking time just a little because of losing heat when you open the door but I usually don't notice it with mine . What's the difference with a pork butt , 9 hours instead of 8 or whatever ? I'm cooking mine just for myself so I don't really care if it takes a little longer anyway . Just have a good time while you're doing it .