For the inverted flat spin you want both aileron and rudder sticks going in the same direction.. Think about it... When you roll inverted, right rudder stick input makes you yaw left and vise versa, while the ailerons stay the same. Since the rudder reverses when inverted, you will have opposing deflection with both sticks going the same way.

I've found that if you have enough power to go from a hairer to a hover, then you have plenty of power for a climbing flatspin even if it does climb slowly.

Let us know what you figure out!
Matt