One thing to consider is with the DRW the wheels are HUB centric. meaning their meant to bear the weight and force of the load onto the axle hub NOT the studs like an older conventional truck rim with tapered nuts.
I was investigating using two ALCOA wheels side by side in the rear of my F-350 as the inner steel wheels had gotten bent twice from the heavy loads and massive pot holes that seem to be getting worse. But I REALLY Didn't like the amount of hub engagement that the outer wheel had with the added thickness of an inner aluminum wheel.
You already have thought about the tire rubbing being a problem which is good. I have seen failures from the two sidewalls rubbing together going down the highway. IT creates a substantial amount of heat in the tire which will lead to failure.
Another factor to consider is Even the E load rated mud tires are really not as tough as a commercial E rated tire. I have seen guys pulling MASSIVE toy haulers with D load range tires and its only a matter of time before something catastrophic happens.
dollar for dollar these are the best tires for an over loaded 16" wheel that needs to operate in rough areas.
http://www.michelinman.com/tires/light-truck/xps-traction/#sizes-and-specifications