To clarify for the newbies reading everything and trying to sort it out;

A longer, and heavier flybar will improve flight characteristics on a Collective Pitch (CP) style heli because the pilot actually controls the flybar and the flybar controls the rotor.

A Lighter and / or shorter flybar will improve flight characteristics on a Coaxial (CX) style heli because the pilot actually controls the lower rotor and the upper rotor stabilizes the heli thru gyroscopic action. A shorter / lighter flybar has less ability to prevent the heli from moving.

Right?
Soloboss