Lower body for me is harder than upper body. In an active hunt my legs generate way more heat when using the same weight as a top. In addition to that my pants typically have less breathability due to the desire for more durability and water resistance. I can't picture using over a 200 weight merino as a base bottom unless you are stationary. Even then a fleece will have more warmth per weight.
www.rokslide.com
This is the first year I've even considered wearing a midlayer on my lower body. The Kuiu 97 zip offs over a merino base, then my pants of course, worked pretty well and the 97s are extremely light to carry in the pack. That said, I also added a pair of the Kuiu Kenai pants late in the season and I much preferred those on the outside when I got stopped versus putting a midlayer on my lower half.
Not to speak for @txtransplant but I've had both and each has it's perks. Neither is designed really for water resistance as they are active insulation and need to breathe. Both have a DWR treatment though.
I haven't had them on in anything more than a drizzle, but that little bit of water beaded up on them pretty good. I wouldn't necessarily wear them in any significant rain, but they're ok in light moisture. They are very breathable, which also means they're pretty much a screen door for wind. They're soft, very quiet, and seem very delicate - I haven't damaged mine, but I don't wear them at all unless I'm stationary. No pockets, but you can access your pant pockets through the side zippers. Very easy to put on and take off; they're basically just like Kuiu's zip off base layers with full length zippers and velcro waist tabs.
