Hi Psyko.
I know where you're coming from, it's tricky isn't it? I've been through exactly the same problem as you. I had a decent setup for one track, which I tried to apply everywhere, but of course that doesn't work. Like you, the problem for me is where do you start when you have nothing to start with. I don't have time to sit there lapping over and over again, trying one thing then another.
Having said that I have done a certain amount of testing, and it certainly helps to make you a better driver - which as Micky says above is half the battle - it's not all about setups. The guide that Micky gave is a good one and I will also be using it as a starting point in the future. I always start with the gear ratios, locking into 2nd gear (does this work for every track? I heard otherwise....) and then as Micky says getting the wheel lock and the sway bars right helps with the cornering. Then I play with tyre pressures - I seem to find higher pressures good for F1, higher speeds and quicker breaking times. Beyond that I'm still clueless - shocks, springs, weights, no idea.
It would be nice, as you say, if there was a 'standard' setup for each track, for each formula, which we could then go away with and tweak if we wanted to. On the other hand, if someone's spent hours of their life getting it right, why should they give it away just so we don't have to bother?!
Good luck.