dash6, Smokey,
You don't need to transition to wing down to stop any sideways drift. If you hold the crab throughout the round out & hold off the aircraft will continue to track down the runway. As the nose rises to the landing attitude you feed in rudder to align the fuselage with the runway.
Applying rudder will not change the direction of travel of the aircraft, certainly not in the couple of seconds it takes for the aircraft to run out of energy & touch down. Crosswind or not, the aircraft will continue to track down the runway after you put in the rudder. The only thing you need to do with the ailerons is keep the wings level.