Ideal vehicle area calculation method?

[AnuragTangra]

Greetings team,

As a member of the esteemed aerodynamics department in our Formula Student team, we're embarking on the development of an innovative aero package for the upcoming year's car. Our recent research has revealed that calculating Cl and Cd values for the entire vehicle necessitates distinct areas: the top for Cl and the frontal for Cd. However, our department has traditionally employed the same area for both calculations to simplify the process, potentially compromising the accuracy of the Cl and Cd values. In light of this, could you kindly advise on the most suitable method and the specific area your team considers? Your insights would be greatly appreciated. Thank you for your assistance.