To recap

Standerd tuning:
Vampira
Quiet Riot
Wild Colonial Boy
Two Weeks
Funeral (?)
Deep Peace (? sounds like its in open C to me)
Sunshine and Happiness (even though Dev doesnt play guitar on this one)

Drop D:
Detox
Things Beyond Things
the Critic
The Filler

I guess some of this is speculation too...

Deep peace is in open c

i thought so too, some one said its in standard....

Deep Peace is Open C. Listen to the root note on the lowest chords (C). It's not possible in standard tuning. Also, the arpeggios during the solo section are pretty easy and fluid to play while in open C.

I'm pretty sure the entire Terria album is Open C. It all flows together like one big song...kinda.

Having tried to play the Deep Peace solo in standard, I'd be surprised if the song isn't in open C. It's just too awkard to play. Then again, it goes without saying that Devin is a hell of a lot better at playing the guitar than I am, so maybe it is.

Of course it's in Open C. Watch Safe Zone, even.

Deep Peace is most definitely in Open C. The Safe Zone medley of it and Away should be confirmation enough.

But also, consider this:
No one intentionally makes their stuff hard to play. They play what they are comfortable with.
Since Deep Peace is fairly simple in Open C, any part of it, and it's fucking murderous to play in standard, why would he ever play it in standard?

Also, if your ear is good, while this is mainly noticeable on acoustic, you can usually tell if someone is playing open notes or fretted notes. The transition between the two main chords in Deep peace couldn't have those continuously ringing strings in standard tuning.

I play Deep Peace in Standard EADGBE but it's not practical!