It were stated that his left hand is occupied, so yes, in his right hand. As he attacks after the bat has passed, it could only be right to left and to the forearm closest to him (right forearm). The mist was launched before he jumped forwards, the line "The better for Vos, as he were about to barge through that mist" clearly indicating that. 4 feet is the distance, the sword's length and the right foot cutting down 2 feet from the initial 6.