Yeh, my guess would be that it depends on the situation and environment as to which would be more appropriate. Like the 'track' surface, the fact that the car will be running straight and so on. As we know, some aero setups are more susceptable to environment changes than others so perhaps it would pay to run a conservative setup, rather than risk a takeoff situation.
I don't know but perhaps some of the earlier 'long tail' LeMans cars, except a certain flying Merc Benz, would provide a good guide