Flat spins are a lot of FUN, I have a DP Edge 540 with a ZDZ 50 and it flat spins well. They look awesome with smoke on. To recover with power, apply opposite rudder and full throttle to power out. Without power (I know because I have deadsticked in flatspins before) you need full down elevator and opposite rudder to get the nose down and gain airspeed, if you don't the plane will continue to spin until it meets the ground.