If you know what you are doing with each adjustment, the time difference for setting up the rear should be trivial. If you don't know exactly what you are doing, you are more likely to stumble upon a set up that works when using fewer rear cogs. For the front, while I've never used Campy, knowing how it works it has to be by far the most forgiving up front (not that non-Campy is very difficult to set up). As you probably know, a double crankset will be easier to set up than a triple, but again, if you know what you are doing the time difference is minimal (a little more than trivial).