WDH bar selection

I contacted a local hitch shop here yesterday that sells Equalizer, Fastway E2 and Reese hitches. What they told me is not to exceed the bar rating but that the manufacturers usually allow each weight rating to overlap with the next lower rating. So as it was explained to me that 600 lb bars would cover 300-600 lbs. 800 lb bars would cover 500-800 lb. So in my case at 4800 lbs wet camping weight and a few pounds in the TV I would be over 500 lbs and the 800 lb bars would be the correct choice. If I was towing the totally dry trailer with no weight in the TV then I would want the 600 lb bars because the 800 lb bars would not be able to easily go to that low of tongue weight. If I ran a 15% tongue weight of the total GVW of 5400 lbs then I would need the 1000 lb bars but if I didn't load everything to the max I might not be able to adjust for a 650 lb tongue weight. I really didn't like calling them and picking their brains and not buying from them but they are $155 more than Etrailer for the same hitch. That's the price of a new P3 controller.