>> “grape juice” <<
.
Don’t kid yourself! - He’s a stickler for tradition, and there was certainly no grape juice available for Passover until the 20th century.
I heard him make a comment about it being grape juice during one of his TV presentations. Other than that one time, I honestly don't have a clue. I've never been to one his live seminars so I wouldn't know about those - wouldn't doubt it either. He is a stickler for detail as is readily apparent.