Here is what I am experiencing, can anyone offer advice to make interrupts more useful?

Does anyone successfully use interrupts regularly? I've been trying a team with two interrupts, just regular interrupts without control, but it seems they only work about a third of the time. If an opponent activates their mystery before a round starts and I have the higher initiative and positioning then they will usually (but not always) work as advertised. However under any other cir*stances it becomes more complicated. Even non-prompt mysteries such as gaara's barrier skill sometimes cast without any visible sign so I can not interrupt them without guesswork. Furthermore it seems that when responding to a prompt mystery it is often too late. Serverside the skill has already launched, any player that saves their mysteries for after the first standard attack is effectively uninterruptible. Against lightning main it seems to happen even if they activate lightning armor before combat begins, I wait until they have the visible aura of casting to target them for an interrupt but they still finish casting before the interrupt launches. For more purposes I've resorted to trying to anticipate what skills the opponent will use and using my interrupt ahead of time. This issue seems to happen most frequently with lm, fourth ay, gaara, and sakura. When testing it against members of my group my first position kakuzu with 5500 initiative routinely fails to interrupt their third position 2500 initiative light main's lightning armor if I wait for visible indication that they are casting. However if we both activate it the moment the keys become available it will interrupt normally.

I'm writing this under the assumption that I am failing to understand the nature of the game mechanic rather than it being a bug. So if anyone has experience making interrupts work reliably I would greatly appreciate advice.