It is better to have the line go slack on one side, rather than get tighter. Both of my pull-pull setups go slack with rudder input due to imperfections in symmetry.

I still don't see the advantage of the servo 'wheel' other than changing the rate at which the rudder moves.

Call me biased, but I think the best engineers are the ones who grew up with hammers in their hands and ended up graduating from an engineering school.