Garf
you sure you have that right, I seem to recall when discussed before the Isolator is the first valve you shut, and its stays shut until after you have shut and opend both rh and lh pillar valves, other wise you wont be able to tell if its the pillar valve/reg/hoses or the manifold. If you breathe down both regs and its still blowing you know its the manifold. Or have I mis-understood the drill?
Hell of a post though, you not busy at work
Matt
Edit _ Janos, I though that was the whole point though, you drill it in until it becomes second nature, so when it happens in real life you just go through the motions without any concious thought, that way you dont make a mistake. (in theory of course). Personally I would isolate as a first port of call then work out which valve needed shutting (if possible). I wont mention indies or inverts as this is in the DIR section.