[Festus2]

Papa Bear -
Given the data that you have outlined in your post, by the time you add all of your camping "stuff" in the TT and in the Nissan (passengers, fuel, hitch weight, etc.) you are probably very close to being maxed out.
I think it is important to realize that the addition of airbags, spring helpers and other similar devices (RAS??) do not increase the carrying capacity of the TV. While add-ons such as these may help in the comfort level of the ride and make the TV and TT sit evenly when hooked up, that is all they do. They do not enhance the capacity of your TV to pull heavier loads.
I am not familiar with Nissan's Tow Haul configuration as to which gear or mode to use to give you the best towing results. That is best left to those who are knowledgeable about that system and what works best.
Again, I would highly recommend a trip to a weigh station. This visit should be made with your TT and TV loaded in such a way that would be considered your normal packing and loading weight - including wife, kids, dog(s), and all the other "stuff" you take with you. Knowing the axle weights, etc., should provide you with the information you need to make an informed decision.