Dblbogey,
So lots of info for you to consider.
As dirtsailor said you will experience some temp changes when loading the smoker. Plan on it.I would kick it up to a higher temp, load and then allow to settle. Since it is gas it should be easy to keep at a level temp. Experiment with different cook temps.
Traditional is 225 till it reaches 165IT then they wrap in foil until 200-205 then rest. This way you may experience a long stall. Myself and a others will crank up the cook temp to 250-275 and do not wrap till the rest period.
In my humble opinion where I see most cooks go wrong is the temp they pull the meat from the smoker. They forget or do not know about the magic of carryover cooking. It is a natural occurring process that can help or hurt you. Basically in short it is when the OT and IT balance out. I have seen as much of a 15 degree increase to the IT when double foil wrapped, then wrapped in towels and placed in a cooler. So I plan on this and remove my meat when it reaches 190IT and allow to rest for an hour before finger pulling. I have not had any issues with the bone coming out clean.
So once you have the cooking techniques down, you then are ready to look at rubs, brine's and foiling sauces.... you will find a ton of ways to do them and they all work, just different ways and preferences.....below I will share with you how I do mine.....
Prep & Rub:
JarJar Pork Rub Recipe
I take the skin off and most of the fat off. I do not use any mustard or binder to hold the rub on. I seen to go back and forth between seasoning the night before or just before going into the smoker. I get great results from both.
My rub is on the sweet side, but is not overly sweet. If you want heat just add some chipolte powder or red chili powder.... the wife does not do heat so I do not use it... When I am doing my cooks I look for a certain color on the bark. Nice and caramelized but not overly dark....
Brining:
I do not brine mine, but others do.
Injection:
I personally do not inject my butts or shoulders. I am thinking of trying it with my foiling/finishing sauce and seeing how it works out, just have not had a cook recently...
Now on a Food Safety Side: If you do choose to inject your meat. It is strongly suggested that you follow the 40-140 in <4hrs Guideline. In short you have compromised the whole muscle with the needle. By doing this you have increased the chance of introducing little bad bacteria to the inside of the meat. So you will want to have the smoker hot enough that you can be at 140 in under 4hrs, then you can turn it down to finish the smoke....
Foiling/Finishing Sauce:
JarJar Foiling/Finishing Sauce
Many out there. It really comes down to what you like. I would at least put the juices from the foil back into the pork as you pull and mix it.