I highly recommend at least 4-8 inches of positive ease. There are two length options in the pattern. The longer oversized length is listed in the pattern, and the shorted more fitted length (as pictured) is in blue). Because of the full cable repeat for all front and back pieces, some sizes have larger backs than fronts, and larger fronts than backs, but will equal out at the armhole decreases which are designed to re-align the sweater so that the shoulder size is the same front and back, and the extra cable repeats wrap around the sides to achieve as many size options as possible.