Exponential is used to make the sticks less sensitive around neutral. The percentage of expo refers to the amount that the stick is less sensitive than it originally was. 30% expo = the stick being 30% less sensitive AT NEUTRAL than it was before. 3D flight is a term for maneuvers where the plane is no longer flying but is kept in the air by shear power and prop wash over the control surfaces. Thrust to weight ratio is actually about 2:1 for good 3D.