I havent had any hassles with the std G4s brake linkage although i have changed the ally piston that presses against the brake pads to a thicker one.
This made the brake movement less and it doesnt have that dead spot before the cam turns and pushes the piston.
I used a flanged ball for this and it sits perfectly in the hole just had top sand the ball side to shorten its height about a mm.
similar to the ones in the link below.
http://www.amainhobbies.com/product_...oducts_id/2741