With sweep, there is also a shorter functional span, reducing radial moment for the same wing loading. An aspect ratio "decrease". By coincidence, dihedral resists the roll, due vertical load, anhedral increases it (rate). Also, empty tip tanks help, they are released prior to the "knife fight". (Olden days speak).As Rudder induces Yaw in the Airframe (per PA), a swept wing ( outboard) gains effective lift, frontally, increasing the rate of Roll.