[Pathfinder75]

Same Long Bed Ford you describe. I was afraid of not having 6" bed rail clearance and felt Hitch weight should be forward of axle so the weight would be spread a little forward. I mounted the Pivot arms as described and shown in instructions Highest Position 18-3/4" and turned to position "B" closest to cab.
While the Hitch Pin on your trailer may have a different length (Mine is a 1116 Lippert) yours may be same but a Morryde possibly RPB72-1116 which is same size.
I have just over 6" bed rail clearance and good turn clearances. Now the front storage door on trailer will not open far as it hits truck. I do not think it would open much better even with Pivot Arms in aft "A" position.
The Truck does settle 3" (measured at axle - top inside of wheel well I believe if memory is correct 44" decreasing to 41" with trailer) from idle to loaded with trailer.
I figured I have to start some place so start high. I have made NO changes so it remains the same today. Thinking hard about getting the MORryde Pin Box to adsorb some chucking on poor roads. I believe you will have this or similar pin box (The High Country doesn't come with that upgrade)
ENJOY YOUR NEW SETUP.