Having run through The Gathering Storm and finally got to grips with the magic rules (no wizards in my party), it occurred to me that tracking power, channelling and other magic gubbinz for NPC's is a bit of a faff and freezes out PC's. However, the option of just casting every round (as suggested for on NPC in Edge of Night) seems too powerful. So, I've come up with the following:

NPC spell casters always have power/favour equal to their WP. Spells/Blessings which require equal to or less that this total can be cast normally each rough, as if they were a normal action. Spells/Blessings with a higher power/favour requirement add a misfortune dice to the casting roll for each power/favour point in excess of the NPC's equilibrium. Miscasts are handled normally and reactive spells (such as Skitterleap) always add misfortune dice equal to their power level (to reflect the urgency and potential lack of available power).

Do you think this will work, and are there any obvious pitfalls that I've not seen?

Spell casters are rare in our campaign, but when the players do meet them I want it to make an impression. But having to roll for channeling AND spells takes time. I like doing it though, because nothing frightens the players more than a dark wizard channeling power over two rounds only to unleash destruction.

But you could also just save up power for spells each round without roll by adding his will power to the total power each round. Decide on a spell and start putting tokens on it.

As for quick casting you can simply add the challenge die if you both add power and cast a spell in any given round.