On our own boats we do this..Steering servo B is mounted beneath the servo mounting plate.     Servo C is the throttle servo. Servo A is the reversing servo.  Servo A can be connected to just one side of the reversing plate but its much better if its connected using a pushrod as shown.  This is made from 3.2mm pushrods silver soldered or soft soldered together.  If they are soft soldered then reinforce with thin wire such as fuse wire or thin electrical wire.

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