Not sure what made the decision, but my '84 is curved. Course even the sides are curved on her so maybe that was a factor? Yeah, there's got to be some slope, even a little, or water will just pool and that's never a good thing. Could be there's a tad bit of sagging which is causing some of the flatness too.
Eric, Melanie and little Maddie, 15lbs of Malti-poo energy
1984 Southwind Eagle I (she might be old but she's capable)