Of course, the rudder needs to be 100% mass balanced just like all other contrtol surfaces! When I said the manual 'tells you to do it', I was referring to adding weight only....(4lbs in the rudder top and 2 half round bars along the bottom 1/3rd leading edge). The manual is silent on the reasons for doing this.

My choice is to place all the weight on top and as far forward as possible, thus requiring less weight overall for 100% mass balance. Of course, I went ahead and closed out the top of the vertical stab so this will need to be redone to accomodate added weight at the rudder top. This is not the first time I've had to plow the same field twice.

Angier Ames