The guys tha defend towing a heavy, long, tall trailer with a SRW have either never towed with a dually and dont know better or are in denial. I have the same trailer as Corb and warned him about it a couple years back, guess what he bought after a not so fair weather trip, F450. The biggest thing is pin weight. Truck might hold the weight but you are either overloading or near the limit of the axle, tires, etc.
Power is not a problem in the 6.4 or 6.7. It is the ability to hold the weight. My dad and brother both went from SRW to Dually and now both are back to SRW and regret it. I have been in some small towns, toll bridges, etc. with my fiver and dually. If the trailer fits the dually will, so width cant be a factor. The only difference on width between a SRW and DRW the fenders, but they are inside the mirrors so that really isnt a factor.