I feel our 2007, E350, 11,500 GVWR chassis is okay in back and harsh up front because the front is too light for the Superduty E350 front coil springs. I bought lower rated front coil springs to closer match the actual load with consideration to trip weight including us two people in the front seats. I don't think I will get to the spring-swap project until next spring.
This diagram of our rig visualizes the load distribution. Our rig here has the 158" Ford wheelbase. I think the condition would be greatly improved if it was built on the Ford 176" wheel base. Unfortunately the floor plan could not accommodate it.