Hodge has summed up everything so nothing else to add
Do you have a part for those rear springs? did you by any chance measure the free lenght on those springs ? who spec'd the shocks ? or that is how it comes from the Mopar 2" kit ? that's astonishing long for 2"... damn.
In any case, stock shocks are around 25.50" extended 16.50 compressed (14 crew cab express at least), so at 29.50" you're 4" above stock. You added 2" bumpstops ?
Icons 2.0 , part#216524, off the shelve are 27" extended, 16.6 compressed, You can call Icon and ask them for a custom lenght same or similar to your current shocks.
Icon also offers same shock with a reservoir that would give you more control if you tell Icon what you're experiencing now and what you want out of your rear suspension. part number for the off the shelve application with the reservoir is 216524R, revitupmoto33 run those in his 1500 CC and he's got a heavy setup with a cap, solar panel, water tanks and some other goodies and he's giving them hell in the dirt without a sweat on 35's, You'll have more lenght customization out of the model with the reservoir just because the IFP is located outside the main shock. and you'll be able to run them harder for longer. More money but trust us when we tell you well worth it. You wont believe the difference those 6112's will make in the front and a good valved 2.0 shock with res will do for the back, Icons are diggresive so should match your 6112's diggrsive front.
BDS have Fox 2.0 part# 98224758, 28.00 16.60
And part# 98224759, 30.05 18.45
Zone also have Fox 2.0
Zone-Fox 2.0 (Adventure) 98450757 Rear 27.95 17.36
Zone-Fox 2.0 (Adventure) 98450759 rear 30.05 18.46
That may work for you, if you can run 29" extended now maybe an extra inch will work but you'll have to check, these are their options for their 4-6" lifts.
All of these shocks will make a nice difference from what you have now in the back, but the Icons with res valved a little heavy will allow you to bash the truck, there is a big difference and it all comes from the valving and the external IFP.
Hope you have fun my friend