Mind you, I dont live in MO (snow & all), but I dont have to babysit too much, even though I use an offset. I'm thinking you may be doing a few other things less-than-stellar that may be hampering your efforts.
That aside, way back when I had a much smaller offset and could only cook 20-30 lbs of meat at one time, I used a trick to help. Shhhhhh. Be quiet now. Dont tell anyone. It's called an: Oven. Yep, put the meat on for 3 or 4 hours on smoke, then bring it in, foil it up, put it in the oven for the remainder of the time. Side benefit, the house smells like BBQ. I still do this for smaller cooks when I want fresh BBQ at 9am in the morning. I'll put it on smoke for 4 hours, take it off around midnight, foil it, in the oven it goes and shut-eye I get.
No need to spend extra money.
Hance - Lake Dogs Cooking Team - MiM/MBN/GBA CBJ and comp cook
Lake Sinclair, GA (strategically about an hour from darn near anywhere)
Started competing in chili cookoffs back in the 1990's and have competed in more than I care to count. I became a CBJ in MiM in 2005, then MBN and in GBA in 2010. I've probably judged 130+- BBQ comps (sanctioned and unsanctioned) over this time. That said, I really enjoy competing more than I enjoy judging, and hope to get back to doing 4 or 5 a year in the near future.