Ok, thank you. One more question. If you're sustaining an Zoe sustain, do you have to have vision on the area as well as the new location?
Say I'm sustaining an area of darkness in a previous room during a run. We just opened a door and there's a guy in the next room that I can see, but the area of darkness is now out of my LOS. Can I move it or would I have to drop the spell and recast it?
I assume you mean zone sustain? I believe spells that can move are called out as such. But I can't think of any off the top of my head. If you could move it, it would make sense that you have LOS, since you are effectively modifying the conditions of the spell form.
Assuming you can't move it, you have two options. As you suggest, dropping the existing one and casting a new one is fine. Or you could sustain the one darkness and just cast a new one. Just remember your -2 cumulative dice pool penalty, per spell, due to spell sustaining. There's a reason why Focused Concentration is invaluable.
If you're initiated, and have the appropriate metamagics, Quickening and Anchoring open up as options. You could then Quicken the first spell, and cast with no sustaining penalty, as the spell does it automatically. Additionally, you could Anchor a spell to trigger in reaction to a predefined situation. Like anyone touching a door might trigger a darkness or chaotic world spell. Neither of which cause sustaining penalties. That said, it's karma expenditures so it's not something to be done lightly.
-Ariketh