I have recently fitted a complete set of bodywork. I agree with the advice given earlier. I would fit the screen to the fairing first and then put the fairing on the bike and mark the mirror holes etc. The screen holds the "ears" of the fairing at the correct distance apart - if you drilled the mirror holes without the screen fitted the screen might not fit.
Be patient and don't rush it - as if you were having sex or drinking a nice Rioja........
Thanks for that advice, Ricky. I have a c/f nose cone that I am saving for when I feel confident enough to try to fit it. It's this sort of hint that can make all the difference between a successful job and my usual efforts!
You will find that using a stepped drill is far easier and causes less damage to the fairing as it is not trying to pull itself through the panel like a standard jobber drill does.