connection between front and rear throttle

For those that installed pilot and passenger throttle controls, what did you use for the connection between the two systems.

Straight steel rod connection?
Cables?

Thanks,
Tom H.

Here's a picture of the linkage rod between the passenger and pilot throttles ...

I used thick wall steel tubing, the ID was slightly smaller than the tap drill needed for the end links. Sorry I cannot remember the OD. Working well so far...

I had a local shop make a cable, basically a shorter version of the throttle and mixture cables. It works really well. The only thing I've found is it never gets used. If someone is flying from the back seat I usually manage the throttle because the passenger can't see the engine monitor.