The pork butt is more forgiving than other types of meat which can be smoked in your CharBroiler.
Your first step would to be to get accurate temperatures on a test run with a fatty. The electric version would be easier to control the temperature. The offset will be a little more difficult due to the air leaks. In the offset use charcoal with wood chips or chunks rather than just a wood fire.
Remember in both cookers use your water pan as designed for a heat diffuser to avoid spikes in temperature.
For a pork butt at 250 degrees cooking temperature, allow 1.5 hours per pound as a guide, check the internal temperature anywhere between 190 - 205 and is done when the bone wiggles without resistance. Move to a foiled pan and rest in an insulated cooler for aprox. 4 hours.
Some pitmasters foil the pork during the cook, some of us don't.
You can go to
meat smoking calculator and find your options, it will give you a timeline of approximations of when to foil (if chosen), when it is near finish temperatures, and when to rest. It is a nice tool for the beginner to build confidence in themselves for the first few cooks. Once you have had a couple successful cooks you can cook without the calculator very easily.
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