Here is a detail picture of my throttle landing gear interlock at the carburetor end. The throttle is partially open in this picture and the gear is locked so the plunger that extends out behind the throttle quadrant is retracted in the picture.
Here is the other end. This is in the right wing. The push pull control has a .078' dia. wire and is Teflon lined and operates smoothly. The clamp is a split block of aluminum made to clamp to both the lock lever rod and the .078 wire plus there is a set screw over the wire and the rod for added assurance that they will not slip. The end of the control cable is clamped to a bracket (black) that is attached to the spar.
I did not measure the throttle travel to maintain 1700 RPM but it is surprisingly short at maybe 3/8 "from idle. I mention this as a starting point for setting the position of the quadrant.
So far I have only operated the landing gear a few times but the system works as designed.