1. you dont need rudders then
2. use a two arm servo and link one rudder to each side with thin snake or wire ( for small A-10 eg park flyer, RUDDER NOT NEEDED ON THIS THO )
3. if its a bit bigger plane use a bell crank in the tail to link both rudders together and to the servo.
4. forget rudders
5. you dont need rudders
6. you know by now