Whatever
axle you decide is best for your application depends on several items:
weight of the trailer (loaded for camping... with or without full water tanks (including hotwater heater, full gray and black water tanks and full freshwater tanks) and size of wheels/tires.) Every trailer (owner) that I've met tows something "different." There really is no "standard" or "better." Just don't
fall into the trap, of "close enough." You'd be surprise how much your extra stuff weights.
"Honey, let's take our bicycles (or canoes this trip).
It's all about your needs and the needs of your trailer/tow.
Be safe, you're sharing the road with others.