I tried Dubro four strok linkage on a couple planes and was not happy with it. Like Grey beard, I use cable for my throttle linkage. It is easy to route around things and has more than enough stiffness to do the job. I use a ball link on the throttle arm and that extends it out a little further to the side. Some times, I have had to cut the threads on the solder on end and also on the ball link socket to get enough travel on the firewall side. Just make your exit hole near the center of the throttle arm movement and there is enough flex to accomidate a slight miss alignment.

Don