The dive test helps you determine whether to move the balance point forward or aft. To determine how the thrust angle should be changed, trim for level flight and chop the throttle. If the model has a major pitch down, you need some downthrust. Likewise, if you are flying at low throttle and punch it and you get a major pitch up, then you need downthrust. Thrustline changes are used to reduce or eliminate pitch change with throttle change.

Of course, when you change the thrust angle, you'll have to re-trim the elevator a bit. Repeat the dive test and see how it goes. With a few trial flights, you should be able to nail down the thrustline and balance needs of the airplane.