HazelNuts39:
Just to confuse things a little, D.P. Davies' book uses the name "angle of incidence" for that same angle. However, for many others "angle of incidence" is the angle between the "wing chord" and the longitudinal reference axis. That angle may be meaningful for light aircraft with a straight, constant section, untwisted wing. It is not meaningful for the swept, twisted wings with variable section that are used on modern large transport aircraft. If you want to apply it to the airfoil section in mm43's drawing, the angle of incidence of the horizontal tail as drawn is -13 degrees
The inherent wing incidence in a transport aircraft, provides a level cabin in cruise. True with a straight wing, swept wing, any wing, in light, medium and heavy transports.
The vertical tail with its fixed and moving parts, has its angle of incidence set for optimal longitudinal stability and control. Mission requirements, aerodynamic analysis, wind tunnel testing and past company experience, determine which profile and every other parameter, would be optimal.
Saving aircraft operating expenses is affected in longitudinal channel design, by lightweight, low drag surfaces and CG location. Since installed in the back and designed to counter wing and fuselage pitching moments, one way to reduce drag is by reducing the pitching moments against which the horizontal tail must act, specifically by moving the CG backwards. This reduces the tail pitching moment required, and thereby its lift and drag. It does affect longitudinal stability characteristics, but with the use of augmented flight control systems, is mostly latent to the pilot. Having flown quite a bit in variable stability aircraft and rotorcraft for research purposes, I can attest that this design is mostly safely fliable. Not all designs are equal though, for example the MD-11, in which pilots had difficulty controling the aircraft to touchdowen during turbulence, crashing quite frequently because of that, e.g. Narita about two years ago.