Here are a few pics of my latest way of securing the throttle cable.
A length of brass strip is bent at one end to a hook shape.
A 5/8" length of brass tube is soldered into this hook.
This mount is then screwed onto the pylon, as close to the link as feasable.
A 3/8" length of fuel tubing is slid over the cable housing.
The cable and housing is then put thru the brass tube on the mount. The piece of fuel line is then pushed onto the brass tube to secure it.
Another piece of fuel line is put in place on the cable housing and brass tube on the other (throttle link) side.
Attach the throttle link to the throttle arm.

The ID of the brass tube you use should be as close as possible to the cable housing size.
The fuel line I used was Dubro medium size. It gives a good snug fit on the cable housing and a tight fit on the brass tube. You need to pull on the cable housing pretty good for it to move.

I like that style, I've been using 2-56 linkage. I do see how the flex would be better. One thing to keep in mind with the flex cable, do not let it rub on any kind of metal, it will make your radio go nutts.

The only metal to metal contact on this setup is on the throttle arm itself.
The servo arm is nylon with a metal link. The throttle arm is alum, with a metal clevis. I could use a nylon clevis, but I don't like surprises when they wear through. The entire cable is sheathed with the nylon tube.
The only real metal to metal contac is in the engine itself, where it is needed

I figured you did indeed know about metal to metal contact, it was just for anyone having radio trouble(something to check for).