I run less than 50% at 0 degrees pitch, FWIW. You definately DO NOT need to switch back to normal mode after each maneuver. It sounds like your rotor is unloading a bit once you get into FFF, which is normal and shouldn't pose a problem. If you are really overspeeding this way, then alter your curves to tone it down. Unless you are running a govenor, it is inevitable that your head speed will pick up a bit in FFF.