You probably know this, but setting up the rudder with pull-pull cable system and one good servo will give you the benefit of adjustments for each direction in addition to that of the rudder movement. And it is more 'positive' in control... more reactive. I can definitely feel the difference in the rudder action using pull-pull.

I've used vinyl coated kevlar cord instead of steel wire to get that metal away from the receiver antenna and it saves a gram or two of weight.