I'm going with both a choke servo and the EDR fiber-optic kill switch on my first gasser (an RCS 140).
Nice thing about the EDR system is that if the RX battery or switch fails, the engine will be killed automatically. Same protection while in the hanger or travelling. Even if the primary ignition switch is turned on accidently... the ignition system doesn't have power unless the RX is also turned on. Should help prevent accidents.
Wiring diagrams and engine/ignition mounting pictures of my RCS140 are on my P-47 page at my website below.
Andy Steere
http://astro.umsystem.edu/andy/rc/