I've read different stuff about it, but what I'm interested in is the timing of the gas-blip. Is it supposed to happen as you let off the clutch (just like during the upshift) or should the engine be revved up during the shift and the foot should be coming off the gas by the time I'm letting off the clutch? I've read articles that go either one way or the other, so I'm not quite sure about it.

What's the perfect sequence of actions?