If you configure your servo properly, it will not need to be reversed. There was a time (not that long ago really) when we did not have servo reversing transmitters. But if this is not possible, you have options.
I would stay with an ignition kill as they are safe and have other benefits. I have been running a golden rod cable to my chokes and they work great. I run this back toward the cockpit to a hinged hatch to a little rectangle of plywood that also supports my switches and retract air fill valve. Be sure the cable sleeve is fully supported full length as to not get flex. At the end of the cable where I grab it to open or close it, I solder a small blind nut to give something to grip.

Hope this helps