One small point.  On the ground the flaps are adjusted and faired in at -7 degrees.  In flight the effective angle is different as the flaps are reflexed further up by air loads that may well result in -10 degrees.  This may be simulated on the ground by manually lifting the trailing edge of the flap with it at its electrically powered fully reflexed position and measuring that angle as the effective flight angle.  Don't be timid in lifting the TE.

 

Grayhawk