Passing up on 25 years now with Ford 4x4 Vans.. I am that guy you left a note on the widow of my Van in So cal when you wanted one for yourself many years ago.. ( I have seen so many of those notes now)
LOL, Ujoint is not Hard Core Rock Crawling.. its a Solid Axle .. For Weight.. My Van is a Work Truck will hold its 10,000 pound limit in Lumber and AV goods and still pull a trailer.. And Climb that hill.. Thats whats it s for. The TTB is fine if you want to cruse the Baja.. But most of us need a Work Vehicle The Van is the Ultimate Truck,camper, Play Rig. Agile is a Fine conversion.. but most of us need to maintain the Weight Carrying load of the Van and the TTB does not do that. IT also does not afford the Ground Clarence.
There is a Reason Ford Stopped using the TTB.. But As I said As the Original owner of a 1996 Econoline 4x4 First Built by Ford via Oasis / Salem Kroger until to today I woudl not use anything but a Straight Axel.. And with the Proper Front Leaf Springs now it rides like a car and not like and angry Bronco.