I find the inverted flatspin easiest. Pull up to a safe alt , chop throttle, push the nose over just like you would do for an outside loop.
When your upside down slam full right rudder and throttle back up using the elevator slightly to keep you flat. If your plane is balanced and you got some beef and prop in the engine room you can climb back up in a flatspin. Looks so cool with a rich 4stroke or a smoke pump going. I have some video of this in full scale and RC scale flown by pros. But no way to host it here.
I have flown a plane with the power to do this. But a tail slide and an outside loop was about as much as my cousin would let me try in his Pitts S2-B. I did make him take my picture with the plane afterward though. What a rush.