I also cut my diesel teeth on Del1, with three TDI's then a Sprinter van (rv conversion) life was good until we got our new '06 E450. Usual routine, first change oil change at about 800 miles to full synthetic, instead of a steady near full oil level throughout my standard 3,500 mile changes I needed a quart at about 1000 miles.
For our application, 24' motorhome that is just about two tons from a maxed out chassis the only oil that stays at the full mark is Amsoil. I don't sell the stuff, I don't know anyone who sells the stuff and I don't care if anyone buys it or not - it is the only oil that will stay at almost exactly the full mark until I change it.
Literally dozens of uoa's show no viscosity changes, very low wear levels and no detectable glycol.
All should know that the 6.0 is detuned big time- less than half of the hp- in the E series due to the lack of available space - much much smaller air cleaner and radiator as compared to the trucks.
With the exception of a new starter and alternator it has only needed scheduled maint and yes it is tight in there but really all is doable-with patience.