There's an aspect of Bara Cancels which I had completely failed to notice, but is critical to understanding its execution. This involves the 'hitstop' property of an attack, which you can loosely understand as impact frames. In short, the rule of thumb is to activate your Bara Cancel upon impact. Multi-hit moves are most vulnerable to this because you can buffer the Bara Cancel during the first few hits, then press the buttons to activate Bara Cancel on the next hit.

Discussion Thread: Game Mechanics - Bara Cancels