Reese Dual Cam Size with a toy hauler???

I still like the look of the dual cam best, but don't like the idea of it going out of adjustment with differing loads, or having it act up cause my weight is different.

You are over thinking this. Your tongue weight won't change the position of the spring bar detents. If, and this is a huge IF, you need to adjust anything it would be the tension and that is easily done. If you want the dual cam, get it. Other hitches like the Equalizer also have to have the tension on the bars adjusted if the tongue weight changes significantly.

With a dually you will have almost 5000 pounds of payload, a 9350 pound rear axle, and four skins across the back that are rated for at least 12,000 pounds. You could easily tow the hauler with no weight distribution hitch. Just get a sway feature. You have more than enough truck. You will need an aftermarket receiver.

Get the dual cam set up once correctly and it will work for you.