I can appreicate not wanting to drive a BIG truck in a busy city. I don't mind it so much until I need to find a place to park. 99% of all parking garages are off limits due to my truck's height.
Interestingly, IMO, the factory and domestic manufacturers of springs seem designed simply for increasing the payload without considering ride comfort. I rode in several trucks with after-market springs and was dissatisfied.
Thus, I installed Old Man Emu Dakar F-350 spings (2.5" lift) with a additional 1200# constant weight leaf (carries load of my Hawk camper with hardly any deflection) in the rear pack on my F-250. This effectively raised my GVWR from 8800# to 10,500# and is so certified by DOT in my state. In order to determine the max weight for your brakes to effectively stop your rig, look for the GCVW (Gross Combine Vehicle Weight) with a conventional trailer (a trailer without brakes). My 2003 F-250 has a GCVR of 12500#.
Old Man Emu Dakar springs are designed in Australia and manufactured in Malaysia. The springs are designed for the Aussies to drive 50mph through the Outback with a nice ride. There are more leaves in the pack and each spring is slightly thinner than factory springs. I was told this is where a more compliant ride comes from.
Anyway, I am very pleased with the results.
Take a look at F-150 OME springs offered by ARB-USA.