Global spell tactics ?

[Ygorl]

When you're casting a spell and all slots are full, does it attempt to override the weakest existing spell, or does it pick one at random? Presumably if you're attempting to hijack a spell that's already up by recasting it, it will have to beat down the old instance of itself, but otherwise how does this work?
I've never been clear on it, and didn't find any answers searching the forum. Thanks!

[Yossar]

My Favorites are probably astral corruption (fun for "locking things down" when you've got the majority of your forging and summoning done) and The Wrath of God (for the monthly report of how many enemy units died).

Ygorl said:
When you're casting a spell and all slots are full, does it attempt to override the weakest existing spell, or does it pick one at random? Presumably if you're attempting to hijack a spell that's already up by recasting it, it will have to beat down the old instance of itself, but otherwise how does this work?
I've never been clear on it, and didn't find any answers searching the forum. Thanks!

I've heard that it picks one at random and attempts to override it. That seems to be correct from my experience.

[Arryn]

Yossar said:
I've heard that it picks one at random and attempts to override it. That seems to be correct from my experience.

It's also what's been given as the official answer by the devs at IW.

[archaeolept]

hmm, my understanding was that it would attempt to override your own globals first. can that be confirmed?

ie.

1) tries to override current instance of said global

if no current instance, then

2) tries to override one of your own globals, randomly chosen

if you have none, then

3) tries to override a random global.

but i'm not actually sure about 2. I've had it happen that way, and Norfleet claimed it, but i could have been unlucky...