I question for those who've gotten the timing down on it or close to it: is there a specific frame to loose your shot? Audio queue? What do you use?

At best I've gotten to about 15% success on the shot. Feels like a 1 frame window. Both with ZodaNOR and Yogi's techniques. Is it really a frame-perfect trick? if so any advice on how to more accurately identify that frame would be super appreciated!