I have had good successs using one servo for both engines and mechanically getting the throttle set-up on each carb for each engine.....it sounds wonderful if both engines turn the same RPM.....but if they're a hundred or two off, not a big deal....... .If one servo fails in a mid to high power setting...makes for an interesting flight to say the least......also have a remote ignition kill for both engines as an extra failsafe .......so one way or another ...I can land with both engines shut down if needed.....most important to have identical or nearly identical RPM on approach and landing.........it takes alittle extra effort to get the geometry correct for both engines.....but has worked well for me.....regards...........Bill....