My thought is that 6-7 inches is sufficient unless doing some extreme off roading. As for which to adjust, I think you'll only get a 1.5-2 inch adjustment on your hitch and depending on the current position of your pin box, can have several inches of adjustment on it. For me, the pin box was easier to work on so on my previous RV I adjusted and eventually changed my pin box. With a couple alignment pins you can see saw the pin box to wherever you want it without having to deal with any weight on it. Level is probably nice but if your within 2-4 inches your not going to hurt anything. I run nose low on mine unless I have bikes in the garage and then it sets somewhat level only because it came that way from the factory and it wasn't enough to worry about.