Triton,
Setting per the manual at the 6 inch ride height is for the original size tires, 175/70-13 IIRC. If you are using 60 series tires, the chassis will need to set lower for optimum suspension dynamics. In the manual there is a front view drawing of the suspension/chassis/tire with the suspension in the right relationship. IIRC, and this was discussed on the forum for a long time, setting the pivot points on the lower front a-arm at equal height is what you want. In the rear, the manual also has that arrangement shown in a drawing, and the driveshafts are shown almost level, with the inside u-joint slightly lower which you can scale off the drawing.
HTH....
Jerry Rude
4005R