Watch the Bends & Vibrato Exercise 4 online guitar lesson by Jeff McErlain from Beginner Blues-Rock Soloing
I've read articles that SRV used to use 13's or 14's on his Stratocaster. He certainly paid the price physically, as we all know the stories about him super gluing his fingertips together. An important thing to keep in mind when choosing string gauges is to choose the one that feels best to you. There is no competition, except in your own mind, that should force you to use exceptionally heavy strings. A funny statement about very heavy strings was from my guitar repair man when I asked him to put 11's on my strat. He looked at me and said, "Who are you trying to impress, me?" I thought that was pretty funny and very true.