How do I Dual Casting

Alright, so I'll start off by pointing out that this is -mostly- a shinigami issue, but not solely.  Kido is one of the few examples of a character being able to dual cast techniques strong enough to require cooldowns, aside from specialized perks.  Normally, for specialized perks, and since they're tier IV max, it's not that big an issue.  Technically a person could fire -two ceros- back to back oh god no, how does anyone with any other specialized skill deal with that!?

Facetiousness out of the way, Kido raises an entirely different issue.  The dual-incantation perk means a shinigami can prepare two kido of any rank and shoot them off at the same time.  This is pretty neat, and pretty impressive if you have the time to set up.  Get a tier VII shield and a tier VII nuke in a single action, if you spend a bit of time charging up beforehand?  Hell yeah, I'll take that.  But again, it's nothing that incredible or impossible to deal with.  People with offensive and defensive techniques on their powers can pretty much do the same thing, and there's no real problem attached to that.

The problem is that for dual-incanting kido, there's no restriction on the type being used.  Technically I could incant a rank 91 and 99 Hado, and then fire off two tier VII nukes one after the other.  That's pretty impossible to counter, because you'll likely put yourself on cooldown just blocking the first, and you could -maybe- use a tier VI to block the second attack, if your skills were quite high.  Then next post they incant a rank 85 and 90 and they're a step ahead because now you're stuck using a tier V and IV to block two tier VIs.  That's pretty ridiculous, and pretty hard to come back from.

I understand the incantation mechanic of kido is meant to have a meaningful impact on it, and that it justifies certain laxness when it comes to what kido can and can't do.  I won't go into a big discussion here as to whether or not incantations themselves are a significant drawback, or whether or not kido's benefits are high enough to be worth that hit.  That's something we could discuss for a while.  This is just asking how we'd deal with a circumstance of someone performing two actions within the same technique type, of the same mastery.

Hollow techniques and Reiryoku techniques kinda get a pass on this one, because their dual casting is literal dual casting; they charge and fire off two ceros at the same exact time, pretty much.  It's easy to understand how that would work, from a logical standpoint.  There's even rules for determining how cooldowns work when you're using a technique to fire two attacks that both do tier IV damage; I believe the technique guide states each use of a tier IV would increase the cooldown by one post, so they could dual-cast tier IVs every 2 posts.

Dual-incanting however quite clearly states that they happen in sequence.  One, and then the other.  Would this mean cooldowns apply -immediately- after the first is fired, even if the second was already prepared?  Would it get its power reduced as if it were unincanted?  Would it fizzle entirely and do nothing?  Would the player get smote by Yamamoto for even trying?  Would they suddenly incur a whopping eight post cooldown on their tier VIIs, or something of that sort?

The rules don't seem to account for a circumstance where someone does that at all.  Because of how the incanting system works, it -seems- possible to prepare two tier VII attacks and launch them both in the cooldown window.  But as I said above, this flies in the face of all logic and balance.

So while we're here, let's just bring up the question for all races in general:

How does the dual-casting mechanic work with techniques that have cooldowns?