Hello selnekav
The 2 cm between the two arms is very short. I agree with you that the vibrations may cause a problem. Here is a possible solution: Put a Z-bend in the 2-56 rod at the servo end. Run the rod toward the carburetor and well past it, then bend the rod 180 degrees and let it come back to the carburetor arm. Put a nylon clevis on the end of the rod and connect it to the carburetor arm. Now revers the throttle servo. The rod can be bent other than 180 degrees to fit the conditions on your plane.