Agree that AoA is everything.
However, as has already been pointed out, most of us don't have an AoA dial. Therefore, for non-aerobatic flight, we use a combination of pitch and power to produce the required AoA.
Most people have no problem setting the required power. But it takes a bit more experience to be able to set an attitude automatically, without having to think about it. And if you can do that accurately, then your AoA will be correct, and the aircraft will perform correctly.
(Stik - can't speak for IO540, but I love aeros. However, I'm not suitably qualified to talk about how to judge AoA when doing aeros, although from my limited experience I'd say that the flightpath can vary sufficiently that the attitude is no longer a suitable indicaiton of AoA, which is why I've excluded it from my general statement above.
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FFF
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