I used to use cable but I've switched to using .047 music wire in a golden rod inner sleeve (hey if it's good enough for Sullivan Cable it works for me)
I'll solder on a 2-56 threaded coupler and use a nylon clevis on engines with a metal throttle arm. If it's a plastic arm I'll just solder on a metal clevis.

The .047 rod is still fairly flexible but a bit stiffer and lighter than cable. The Servo arm gets a screw set EZ connector..