One suggestionI just thought for the OP:
Something that is noted on the OP is that Psystrike deals more damage with accurate A presses, rather than mashing, but nowhere do you mention which timing people should aim for. From my testing, it seems like this is a good ballpark for the timings:
First press: Whenever you want, it starts the move.
Second press: Around the time where Mewtwo raises its fist up, maybe a few frames before or after that. It also seems to coincide when the particle vortex is at its widest.
Third press: When Mewtwo hits his tail on the opponent.
Is this accurate? I really think the OP should address these button presses, as the damage difference is VERY noticeable (goes from ~90 to ~140 damage) and the game doesn't really give any tips of when to press the button.