Is it just a flat? If it is I would see if you can get your smoker to 250*F and check it after 5 hours. If you need to you can bump the temp up to get it done. You shouldn't have to baste in a UDS. Just start it and get it to temp and put your meat on. I usually put my meat on while the smoker is coming up to temp.
Team: Pyle's BBQ; Yoder YS640; Good-One "Trail Boss" 60T; Weber Kettle w/rotisserie ring; Big A$$ Rotisserie; Weber OTS; New Braunfels offset smoker.
Saddles BBQ Bistro