I’ve towed mine with 2, 3, and (once) 4 bikes on the back. Always lots of weight
forward. No sway, but 4 did make it a bit squirrelly.
The 13’s are pretty stable. I tested the 3-bike set-up to 70 mph and gave the steering wheel a waggle. Came right into line. In the end, the amount of vertical bouncing is what caused me to reconsider. The dynamic stresses on rack and receiver had to be enormous.
In the end I decided the best is... none. We now carry two inside the trailer, and discovered with weight
centered over the axle
the trailer handles like a mid-engine sports car, night and day difference.
This guy needs a Happier Camper HC1