As long as you're looking for a dark, crusty bark (which I think is the absolute best), there is no need to keep the temperature at 225 - 250, at least for the first 6 hours. There is absolutely no problem with blitzing the pork butt with 350 degrees at any time during the first half of cooking. The result will be the same as long as you back down to 225 - 250 for the remainder of the cooking. When I do a pork butt in a 22" Weber, it's usually 350 for at least 2 hours hours each time I recharge the charcoal - the temp usually starts to drop after two hours and ends up around 195 - 225 before it's time to add more charcoal.
I wrote about this here a couple of years ago. I did several documented experiments with it on the forum, with pics and detailed timing/temp notes. Since then, I've probably done 10 butts the same way. There is no problem at all with high temps in the first part of the process. The key to the tender pulled pork that we expect is the final internal temperature. I find the best results with the most fat rendering occurs at 200 -205. You can still pull quite nicely at 195 but there's the chance that you might find a stray small piece of internal fat (excluding the remainder of the fat cap, of course).
This isn't a method to speed things up. It doesn't. I only bring it up to shatter the myth that great pulled pork requires keeping your temperatures at 225 - 275 and keeping your temperatures constant. If you need to monitor your temps religiously because it's part of your process or part of the fun, that's OK. But it's not necessary until about the 6 hour mark. For those who only have a small device like a round Weber, this can be a real help in cooking. You basically just fire it up and leave the top on and walk away until the vent thermometer reads 225 or less (obviously time and temp is dependent on the size of your smoker and the way you vent the device - my figures are based on a 22" Weber with about 1/3 bottom vents/ 2/3 top). Then you fire it up again and repeat the process. You usually don't have to recharge the coal until 2.5 - 3 hrs. After you do this twice, that's the time that you monitor the temperature more closely. In fact, after about 8 hours (another 2 hours of smoke), you can finish in the oven at 250 because you've already injected about all of the smoke that you're going to. You'll get a good smokering and a nice crusty dark bark, Memphis-style.
As I said, this doesn't speed up the process or eliminate the plateau. It just makes it easier for those of us who are using smaller grills. You don't have to worry about fiddling with the coals or opening the top to check progress.
You can't use this method if you have to have a mahagony exterior.
You can see pics if you search for my posts.
