RE: Control twin engine rpm?
I use a JR X9303 transmitter and a separate channel for each engine servo. This transmitter, as well as others, have a throttle curve for each engine(dual engine). By adjusting each throttle curve, you can attain nearly identical rpm on both engines at all throttle positions. If you can use the transmitter, it is a lot simpler than adding another system on board you plane. The synch systems do throttle back the running engine when an engine fails so as not to have a severe assymetric thrust condition. However, several of my engine failures have been during takeoff. I was able to continue flying with the single engine. The synch systems would require you to reduce the throttle positon and then advance the throttle to get power back on the good engine. I'm sure, though, that there are advantages to the using a synch system.