perhaps just some general principles ...
difficult to make a silk purse out of a sow's ear, once a truck always a truck
my truck is at the lighter end of the spectrum so fewer ATW leaves, others are heavier
small diameter rims with large diameter tyres can be more comfortable and flexible than large diameter rims and same outer diameter tyres
strong sidewalls are good for life, not so good for comfort
conventional wisdom is that lower unsprung to sprung weight ratio is "better".
longer springs are "softer" than shorter springs
parabolic are "softer" than conventional leaf
parabolics tend to wear out shocks sooner
greasable bushes seem to be de-rigeur
suspension seats are good, I have sprung thingies
even with all the mods we met roads that we simply left and took another one.
air is good, corrugations are bad.
after all that I would continue the search for a vehicle that doesn't require suspension modification.
I read somewhere the original (front) springs have slightly different set for left and right to compensate for some road camber, as can ATW, don't know about EC.
I had a curved pipe that arched over either of two vertically slung spares, wire rope through middle of pipe to hand brake winch. My chassis was cut short by previous owner, I now have a standard spare wheel chain winch from a big truck for single spare horizontally under rear of sub-frame. High enough to always have access and no effect on departure angle. I'll also carry a spare carcass.