The gate is not split because I don't want a hinge in the middle.
Sides on the dovetail.....Yes.
Expanded metal will catch a bunch of wind. Even if it was a tube structure w/o any mesh it would catch wind. Do some reading about sandrails and the guys say that their car actually has more drag with the tubes exposed. The cars become faster when they put the panneling on them.
Last year I pulled one of my fathers trailers around and the thing had a ramp that was pry 8' tall. It was just a skinny 13' long single axel trailer, nice and light. That stupid thing was harder to pull than the 16' tandem axel trailer I pulled the summer before.