When it comes time to install servos I have found (after many mistakes), that the best time to install servos and pushrods, is as soon as possible. Even if the kit calls for later radio installation in rc planes, I find that it makes for a better install if you mount the servos and pushrods as soon as the fuselage frame is completed. The reason being, that I can maneuver the pushrods better and there are no obstructions which can lead to poor pushrod installation.
The pictures shown here depict the servos installed inside of a fuselage that still has plenty of open space and very few obstructions. This lead to a successful pushrod installation that minimized any binding of pushrod movement due to poor pushrod tube placement. For the beechcraft bonanza model airplane, I need 2 servos to hook up the torque rods for the ruddervator, you can see the pushrod and nylon clevis that will connect to the torque rods for the ruddervator.
Frustration Saving Tip: Whenever I install any nylon clevis, I always add a piece of silicone tubing (fuel tubing for rc gas engines works the best). This little insurance piece adds piece of mind that my clevis will never come undone in mid-air. It is a simple way to reduce loss of control in the air. So add it to your building habits and you will be that much better off when it comes to building and flying your rc airplanes.
When I was satisfied with my pushrod tubes, I glued them in place TIP (make sure that if you are using plastic pushrod tubes that you sand the outside of them before gluing them, otherwise they may not stick). I will add some pictures to this post of the pushrod tube installation when I have some more time.
To finish up the pushrods (which in this case were 1/16″ diameter metal rods, threaded at one end). The pushrod end that will connect to the servo needs some type of threaded coupler. To connect the servo arm to my pushrod, I chose a brass threaded coupler (this is pretty standard). I like using these for the simple fact they are the most reliable. As you can see in the pictures here, I have a vise set up to hold the rod while I use a propane torch to heat the coupler.