I have heard some say no rudder needed but I never saw it that way. Scott McHarg mentioned in his last
K Factor article that rudder is needed. One way I have worked it is on the sim go up several hundred feet in "follow behind" view mode and do slow rolls as viewed from behind. I also with the sim set the wind speed to 25 m/s and fly the plane at eye level right in front of my face (normal view) and try to keep the plane in 1 spot as it rolls. Also try flying straight and level with a 1/8th roll - yes you need to blend rudder and elevator to hold straight and level. Seems to me, it's all about the blend.