Contact your dealer and express how disappointed you are are how the rear squats beyond level without having a serious load on the rear. Many have done this and have gotten the blocks changed. The only thing missing from the rear of your F250 vs a 350 are the taller blocks and an overload spring. With the taller blocks, it will be close to level when towing. I have a dually and I even have airbags. I can adjust them on the fly with my onboard compressor. My pin weight is 3100 pounds.. Before coming out of pocket for it, see what Ford will do. Many are much happier now.
2012 Sandpiper 365SAQ weighing @ 15k, Onan, 2nd air, slide toppers, TST
2013 F350 6.7L Lariat 4x4 CC DRW,Viair 1007, Ride-Rites, Edge CTS, B&W
2001 Chevy 3500CC DRW 4x4, 8.1L, 4.10 gears w/ Detroit TrueTrac
2001 Ford Excursion Limited 4x4 7.3L,V/B Spring Mod, ProComps, Hellwig Swaybar, & other 'Necessities'