David Gilmour lived to experiment whenever he worked with Pink Floyd. None of the band members signed up to make the same bog-standard rock and roll throughout their career, and half of the fun was hearing what new avenues they would go down on each one of their records. But long before they had the lavish concepts behind all of their songs, Gilmour was still woodshedding after being thrown into the deep end of the band the minute that Syd Barr…