RE: H9 Twist 40 engine and prop choice???
I had both an Evo .46 and the AX on mine. It also does a great waterfall or forward flip. With spoilers it is tighter, but tends to over rotate on recovery. Without spoilers it is larger, but stops on a dime. The flip is so predictable you can do them down low easily.
As Walt said, it's a flat spinning fool.