MillerTime-not trying to talk you out of a dually, but....
Like I mentioned before, if your numbers all fit, then go with the SRW. By the time you figure the upfront cost and added cost of fuel (more rubber on the road), tolls, and the cost of tires when you need them, for me don't justify a dually for an everyday ride. Did I mention the pain in the butt parking these things at store parking lots ?(spots are getting narrower)
Sure it's probably a little more stable if your going to travel the flatlands with crosswinds etc.. but as far as ' big trucks' passing you, with a trailer as big as these it really is minimal. It plays more of a roll when towing a smaller trailer.
Some trucking companies are changing over to SuperSingle tires instead of the traditional duals, simply because of cost and fuel savings---just a thought!