Depends on what you understand by the term 'incidence'. The difference between the the wing and tailplane chords? The angle of the wing to fuselage? The angle of the airstream to the wing chord? If it is an ARF, then it is what it is. Modifying the 'incidence' might not be a simple task, but then if the wing setting angle is adjustable, it might be simple. First we need to know what you mean by 'incidence'.
Evan, WB #12.