I would run the pit at 250F to 275F. No need to go as low as 225F. However...
In keeping with your original post, you can most certainly cook both the butt and brisket at 225F, and there is no reason that you will not have good, or bad, results based upon your cooking skills. Give them both a rub, get the smoker going at a clean heat, whatever you choose, look for light blue or non-visible smoke, and get the meat on there. 1.5 hours for a pound is a good estimate for either cut of meat. Important thing here, do not crowd the meat, if there is not at least 2" clear around the meat, then you are crowding the meat and will not get good air flow around the meat, that slows cooking a lot.
on edit: do not cook by time or internal temperature, the only way to cook is by feel, I use the probe method for brisket, a metal probe, skewer, ice pick etc...goes into the flat of the brisket very easily, pull the meat. For pork, if there is a bone, cook until it wiggles easily, if no bone, cook until the meat starts to pull apart when you lift it. Always rest the meat for an hour at least.
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."