Drive smart and you will be fine, no questions asked.
Driving smart also means prepping smart, and having a quality brake controller and functioning trailer brakes.. Even if you don't need them to operate at full stopping power.
Unless it's a windy road with lots of corners you may find that 6% isn't all that step and compression braking does wonders. Just be smart about your speed.
I have gone down grades where I needed to touch my brakes twice, and my buddy behind me, at 2/3 the weight, is nearly smoking.... Use what you have, wether it's compression or an exhaust brake. I would be less excited about decending steep grades with a diesel at GCWR without an exhaust brake thou, they are money well spent.
