If the temp dropped when you buttoned it up you had to much fuel in the box to allow for proper air flow. Small fire box tiny fire, BIG fire box, small fire. A stick burner aint a UDS quit trying to make it act like one. Feed the beast small bites more often. Ask your self is it easier to take small bites of a Pulled pork samich or pack the whole thing into your pie hole at once and try to chew it up... same difference, less is more.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC