Modelers tend to worry, I think, unduly about incidence angles. My original design bipes all use essentially 0-0-0 incidence. I try to design out the need for thrust offsets, chiefly by using subfins and subrudders. Equal rudder and fin area above and below the thrust line will remove the need for any right thrust. If incidence angles were all increased equally, for example, to +6 upper, +6 lower, and +6 on the horizontal stab, and 6 degrees of upthrust added, the airplane would fly just about the same, except that the fuselage would be inclined downward 6 degrees in flight, giving the pilot better visibility over the nose. This is the main reason for using positive wing incidence. It has little or nothing to do with aerodynamics.