As far as ARF's go, incidence is usually set by screwing the wing on, the saddle will only allow the wing to fit one way, and it's usually close enough. As far as your kit built plane, what is it? If you reference the thrust line as zero, you can probably start with between 0 and +1.5 and have a flyable plane. Sometimes you can use the horizontal tail as zero reference. It would really help to know what your model is, somebody out there may have plans and specific info. Good luck.