I've re-watched the Street Magic Series where David Blaine does his double-lifts. I have to say he has one of the smoothest and virtually undetectable double-lifts I've seen in front of a live audience. Which double-lift is he using?
theory11 — Magic Tricks & the World's Finest Playing Cards
The revolve at the base of the thumb as the cards are turned face up stud fashion, is Martin Nash's idea dubbed as Knock out DL ( so I was told .. ) The card can be snapped over or held stationary.