The actual term for the difference between the wing angle of incidence on the fuselage and the horizontal tail angle is "longitudinal dihedral' FWIW.
Decelage refers to the difference in incidences (if any) between the upper and lower wings of biplane..
When the AV Kadet Team isn't flying Kadets, we use the Eindecker...
These are all Balsa USAs, .91 powered.