Took this from an interview he did recently:
"Tuning-wise, there's three songs that are a half-step down in drop D. There's about eight songs that are in drop B, and two songs that are in an open E5 tuning dropped down to B, so I guess it'd be an open B5 tuning. And then another song is a whole step down in standard tuning."
"As for amps, I used a Mesa Boogie Triple Rectifier and a Cornford RK100. Eric Friedman, who did the rhythm guitars, used two Bogner Shiva models, one of them was the 20th anniversary model with the KT88s. The Shivas blended really well with what I was doing."
Eric also tours w/ them for Creed shows, I think last i saw he's using the 5150III, Mark has one now too but it's not in his rig. Mark's live rig is ridiculous. He's using like 5 amps.
Here's the whole interview if you want to read.
http://www.musicradar.com/news/guitars/ ... was-548839