RE: Polars for flat (non-airfoiled) wings
Not sure about the Profili issue but as far as the section shape goes you need to remember that the flat tails with movable surfaces are actually a variable camber section. In use the airfoil changes camber as well as altering the angle of attack due to the surface moving. That would be a tough one to study without further AoA data to determine the normal range of operation compared to the defection angles