Mounting the servos as far away from a gas engine is a good habit to get into. Running a long nyrod throttle isn't hard to do and it's a good idea to always use completely non conductive rods that attach to the engine like the throttle. With the 2.4 radios we have today RF is not as hard to remove or keep away from but it can still happen. I lost my last summers build to RF so I know first hand it is still waiting to bite you in the butt! Keep all servos as far away from the engine as you can. Read about it in the gas engine forum.
The spring under the throttle arm can be dis-connected but leave it in place, leaving it attached is also a good idea. Remove the idle stop screw so you can use your radio trim as a way to kill the engine.