I drive a Dodge utility for work and don't carry heavy weight ever. Use it for tool space and ladder rack. Problem is E rated tires just about mixes my nails on the freeway and shakes liquid from cup holder.
Thoughts are to run a P rated 285/70 on the inner and an E rated 275/70 on the outer tires. Anyone think this will cause ANY problems other than wearing the inners quicker?

 

Have you worked with the air pressure? I would also check laws in your state regarding Load Range and Ply Rating (load capacity) to see if you are legally allowed to alter those specs.
I would suggest staying with the same tire for inner & outer. The problem with heavy duty vehicles is the suspension is designed to carry a load. When it unloaded it is very stiff. I would work with the air pressure when unloaded so it gives somes flex. When loaded you will have to air back up.
Let me know if i can help in any way.