Many cut the larger ones in half first and smoke the two halves to lessen total cook time. Most foil during the cook (in the low- or mid-160s) to even cooking, keep the exterior from overcooking, and to lessen the cook time. Even doing that, at typical low/slow temps, smaller chuck rolls can go 15-17 hours, the larger ones 20-24.
I think most find 'done', if temping, in the mid-190s to ~200.