I have a CG pro with SFB. I have extended down my chimney, added 2 thermometers and made a removable heat baffle that gets me within 270 degrees hot side and 250 cold(far side) side, I have also changed out my fuel box in the the SFB. I am having some people over this weekend and have a 9.5 pound pork butt i want to smoke. i can keep around 250 degrees for about 6 hours in the fuel box i have. how long would it take to smoke a butt that size?