What's your mud like?
Here, central LA, you rarely see duals. Maybe in rice country in the southwest prairies of the state where they have 10" of sand and a clay hardpan.
Otherwise duals here are a recipe for disaster, unless you wide space them with picker spacers and put them on 36-38" centers. They pack and will not go forward. In heavy sticky clay ground big singles anyday. 900 radials R-2 or the big floaters with 28L's R-2 in the back.
Next, tracks, rubber or steel.
Every 6R picker with duals are either wide spaced or have scapers between the tires.