You do not want to re-locate the rear or set the pinion angle until you are at ride height like Jerry said. What I meant by moving the front location is only to make the lower bars parallel to the length of the frame. Not to change the height of the front bar.

You have the tires on it. So now put the bed on it and set the ride height (or put the same weight on the frame that the bed weighs). I have always had my trailing arms set at a bit of a down angle because the rear of the vehicle will squat on accerlation. Personal prefferance.