Garyl53, I don't know if this information will help you but I'll pass it along just in case. I would think that what affects the front would somewhat affect the rear.
I started a thread over on the tow vehicles forum about my problem. JIMNLIN kindly posted a link to the vehicle specifications. I found that my 2011 F250 6.2, 4X4, Super Cab with plow package has front springs with a rating of 5,600 lbs. The stock springs have a rating of 4,800 lbs. so a difference of 800 lbs. I think would make quite a bit of difference unloaded.
I got a price from a spring company that said it would cost about $900 for the swap including new bolts. He said the front bumper would have to be taken off to switch these out. I called a Ford dealer up and got a price of $263.38 for a pair of 4,800 lb. springs. I'm sure that different dealers are going to have different prices but this is the only one I called. I know there have to be a lot of used ones lying around but finding them and having the right rate may be a problem.
If I can find a set of coil spring compressors that I think are worthy of compressing these I'm going to change them myself. I've changed coil springs before but nothing of this caliber and it wasn't that hard.
https://www.fleet.ford.com/truckbbas/topics/techspec.html
