Just posting this as an FYI...
akcapeco forwarded me this link - one of the few sources of apparently "official" looking coefficient of drag numbers for the vehicle:
Chevrolet GEO Metro LSi (1995)
1995 CHEVROLET GEO METRO LSI SEDAN: .32
Somewhat close to the .34 listed here:
The Mayfield Company Homepage - Geo Vehicle Drag Data - though this page doesn't specify sedan or hatchback.