this might work for what you have:
cover the top with bacon.
cook at high heat maybe 325 until internal is @ 170.
foil and cook till probe tender poking from the top.
total time should be @ 4 hours max.
the less time in the might help the meat stay more moiste without the fatcap heat "buffer"
i have cooked the last few high heat and they are fork tender and flavorfull.
hope that helps.
btw, do not mop more often. you'll be messing with the heat/humidity inside the cooker and most likely will dry out the meat.