Hi - I recently bought a Prairie Schooner 5th Wheel. I was going to change out the King Pin Box on the trailer - because I will be hauling it with a Semi-Truck. But, have actually decided to mount a smaller 5th Wheel Hitch behind my Semi's current 5th Wheel Hitch (which is for a 5" Pin) The King Pin on my RV is 2". There is plenty of room to mount the smaller hitch behind my Semi-hitch, and it can easily be removed when not in use. Now the problem is that I don't know what size 5th Wheel Hitch to buy. I've been looking at 16,000 lb Hitches - but not sure that is enough. I don't know the Gross Trailer Weight of the Prairie Schooner (it is currently in another state). According to the paperwork it is a 1987 40' Mallard Prairie Schooner 5th wheel with one slider. Can anyone give me a guesstimate of what size hitch would be best. I went looking for a Mallard Prairie Schooner on the computer and could find nothing about that - found Gulfstream Prairie Schooner. Don't know if they are one and the same. I tried contacting Gulfstream about this and have received no replies. I don't want to under buy my 5th wheel hitch - but also don't want to have overkill either. Also - what brands do you prefer. Any help would be appreciated.