Four hours or so before they’re due beneath the massive wraparound video screen at Sphere, Bob Weir, Mickey Hart and John Mayer amble into a backstage production office like three guys showing up — again — for the work of blowing 17,000 minds. “Nice to meet you,” Mayer says, grinning as he extends a hand. “John Mayer, Mayer Industries.
The whiskery guitarist likens Dead Forever’s storytelling to opera; Mayer says the visual content, which he took a lead role in developing with the London-based Treatment Studio, “has a little Disney ride in it.” Mayer came to the Dead relatively late in life after hearing the band’s “Althea” on Pandora; for him, this show represents “a trip through the metaphysical anthropology of the Grateful Dead with Dead & Company as your hosts.