I can't tell you a direct answer as I don't have the same model, but here's what I do to guesstimate the amount of drop needed.
Crank the tongue on the trailer down so that the frame of the trailer is sitting parallel to the ground. Now, measure up to the bottom of the trailer tongue, or whack your knee on it so you can remember that measurement.
Now, walk to the back of the truck. The ball mount should be roughly 2-4" higher than trailer tongue. If the tongue is pretty heavy, you'll want the ball about 4" higher. If the tongue is pretty light, an inch or two higher is fine. You can gauge the ball mount height by the bruise on your knee.
'00 F-150, X-cab, 4x4, Lariat, 5.4L Off-road, Trailer Tow, Holandia Sunroof($1000)Mucho mods
98 Explorer bone-stock (Lemon Law Case in Progress)
Photo Gallery Here
I'm not smart, just a resourceful idiot with some spare time.