I've only done a few chuck roasts, I think if its going to pull depends on the fat content, more fat better pull. I just did two on Tuesday one about 3.5 lbs the other around 5 lbs. I smoked them both at 225, the smaller one I took off after about 6 1/4 hrs at 195 (It was dinner time had to eat something), the larger one at 7 1/4 hrs at 215. Neither were as tender fall apart as a pork shoulder, but they where very Knife tender like cutting almost through butter. One might say I could have left them on a little longer. I think I foiled too late, may have toughened them a bit.
As for sauce. I have stated before I use lots of Cattlemans, so for the roast when I foiled I used about 1/4 cup of drip juice from water pan, and thus when I opened the foil the meat juices plus drip juice made a nice Au Jus, so I go 50/50 Au Jus mixed with Cattlemans, so there is a nice smokey beef flavor to the bbq sauce. The sandwiches weren't pulled beef, they were super tender sliced with bbq sauce and were Yum...
