I agree on not using all-thread rods, since they don't stand up to stress & vibration all that wellthe longer they are the worse they are for durability and rigidity. I like the Darrol Cady rods (http://www.darrolcady.com/Carbon_Fiber/carbon_fiber.htm). You need thecarbon fiber tubes plus the threaded steel ends. The website says (or used to sayI haven't read it lately) you can use rubberized CA to glue in the steel ends into the tube, but I find the JB Weld holds stronger. Central Hobbies also has sets for making up your own CF pushrods, and they are pretty good with technical support if you need a little guidance.

I cut the carbon fiber tube to length with a dremel cutting wheel. I do the cutting with tube end and cutting wheel inside a plastic bag. I can see where I'm cutting, but the carbon fiber dust (nasty in the lungs) gets captured inside the bag. I also wash my hands when I'm done cutting.

The first end goes in with the JB Weld on it, no problem. When you go to glue in the other end, you'll have air pressure resisting the second end with the epoxy globbed all over it, and it tends to push out when you let go of it. You need to clamp the ends in place while the epoxy cures; otherwise one or both ends will slide out while the epoxy is setting up.

I have the Showtime 90, but not the 50, so I'm not sure what the servo mounting set-up is. If the servos are tail-mounted, you can use the Hangar 9 titanium pro-links, which I like very well and use a lot. These are threaded right-hand thread on one end and left-hand thread on the other, so you can turn them with the small wrench they sell as an accessory to adjust like a turnbuckle. They aren't cheap, but they save a lot of time setting up neutral, no disconnecting, turning, reconnecting, checking deflection, disconnecting all over again, many repetitions before you get it right. With the pro-links you're set dead-on in seconds. With a little luck, you will find pro-links of suitable length for both the ailerons and elevators.

Somewhere I've seen ball links with left-hand threads, specifically intended for use with the pro-links. I didn't pay too much attention when I saw them, because I got myself a left-hand tap to re-thread the standard Dubro ball links. Retapping them is a lot easier than trying to force a left-hand thread into a right-hand tapped barrel. I put a little band of red nail polish on my left-hand tapped ball links to distinguish them from the standard right-hand pieces.

I will grant you that all this is a bit more time consuming and a little more expensive than sport model pushrods, but if you want to fly precision aerobatics, I consider it a small price to pay. Also as you go up in model size, this becomes totally standard practice.

For 3D or any other kind of model, this is how I link everything I build. Linkages are tight but smooth, slop-free. Also, don't neglect to seal your hinge gaps for better control surface effectiveness. A lot of little things go into setting up a well-behaved model.

I don't fly helicopters, but I will say the guys I know who do are generally a lot more particular about setting up a model compared to the sport flying crowd.