2012 Harmony Stack

[Infinite Cactus]

What parts did each member usually sing on the 2012 tour? Because of the doubling by the backing band, sometimes I can't tell who is singing what. Specifically though, where were Brian, Bruce, and David in the stack? I think I read that usually Brian would take Carl or Dennis' part when not singing lead. And David would take Dennis'. I also have heard that Bruce tends to sing Carl's parts when it's the MB shows. Any thoughts?