Yes I think all those old rules dont apply as much anymore with modern equipment, still good rules to keep in back of your head. I would not worry about it I would set your servo where it needs to be and use a solid wire pushrod. If an installation on 2.4 lends itself to getting the radio equipment, switches, batteries etc. away from the ignition, do it, but if it is not practical or will throw your cg way off I wouldnt worry about it many manufacturers put the throttle servo 3 inches from the ignition and even provide you a solid wire pushrod, and strap the ignition battery right against the Rx battery.

Go to the Hangar 9 website and look at the instruction manual pictures for the new Tiger Moth 20cc. You basically have the throttle, elevator and rudder servos, the ignition battery, the Rx battery, switches, the Rx, AND THE IGNITION box all within about 8 inches of each other. In fact, they have the RX like 5 inches or less from the Ignition. There is no way to do it any other way in that model, because they havent allowed any space for it.