Prop to Ground Clearance

Gang --

What are y'all comfortable with as minimum clearance from prop tip to ground? Flying off closely mown grass, asphalt, or cardboard on home plate -- Would you adjust the clearance measured to a concrete floor?

Larry. What I do is put my plane on the carpit and put my hand flat on the floor. The prop should not touch my hand. THATS with an low attack angle for take off. OR that's with a long tail wheel. Hope this helps. Scott