Although I "discovered" Roy Buchanan when I was a blues-loving kid in the mid-'80s, the guitarist's first brush with something resembling fame came in 1971, when a documentary, The Best Unknown Guitarist in the World, aired on public TV. The documentary was about Buchanan, a blues-rock virtuoso whose gritty, distinctive technique inspired scores of guitarists, including Jeff Beck.
Accurate string bends and vibrato don't come from your hands but from your ears. They can't be practiced mechanically like alternate picking and sweeping. It takes a more careful approach to develop your ear to hear pitch. I've heard many players who can play extremely fast, accurate scales and licks but can't execute a simple string bend and stay in tune.