How can their aircraft have a right rolling tendancy? We always trimmed our aircraft in level flight at cruise, wings level and adjusted the rudder trim to make it fly straight and level. Of course you have to normally turn the autopilot off in cruise to do this accurately so may be a problem for some. Once you are wings level and steady on heading the ball magically goes to the center so there are no right rolling tendancies. It has worked for decades and saves fuel too.