i have a 30ft 5th wheel i pull with my 2001 f250. the best way i can tell you that i installed the hitch, is run a rope across the bed of the truck from center of rear tire to center of other side rear. now measure 2-3 inches back and that how i placed mine. a little old school method but it works.
i also have a long bed so the hitch is a fixed mount and not a slider. if you have a short bed you will need the slider. you can install a gooseneck ball right underneath the 5th wheel for quick changeover also.
height adjustment i believe is approx. 48 inches from the ground to top of 5th wheel plate. mine rests about 2 inches below the bedrail.
hope this helps