Hey dude. I'm also 5'10" 170 lbs. and I went with a large. My calves are around 14.75"-15" circumference and the Kitos feel tight below the knee and stack throughout the leg quite well. I usually don't fold the cuff in half either.
I like the way the matte black zippers look, but the shiny silver zippers zip more smoothly and aren't really subject to chipping. I like the contrast that they provide against the darker colors like Charcoal or Midnight Blue. With a long track like on the Dual Flash, I actually prefer the shiny silver ones.
It used to be 16 oz. in the website descriptions through 2014, but in 2015 they stopped including it. I got a Black Villain in 2014 and a Black Dual Flash in 2015 and the Flash feels a little thinner. I don't know what it is now, but the fabric has changed since 2013-2014.