Can't comments on the kuiu. But my ambient pull over was amazing on my sheep hunt. Two mornings it dropped to 32ish degrees in the morning and I was toasty with a t shirt and ambient over the top, any wind I would add the wind jacket over the top. Ill be able to talk more to it's cold abilities come November at the end of moose season
I have the ambient jacket and it's surprisingly awesome for what it is. Bought an extra just to wear around town. If you don't need any wind protection, it's hard to beat. Sometimes it gets too warm though which is why I think the hoodie is a better call for you.
For a mid layer I want it to be light, must have a hood, needs to breathe very well, have zippable hand warmer pockets, and dry quickly. I also want to be able to use it comfortably with no layers underneath it as a super breatheable sun shade type shirt (Arizona and Mexico hunts). It also needs to work well as an insulation piece between a base layer and a puffy jacket or rain/sleet/snow jacket.
In trying just about everything for this versatile piece, I’ve settled on the Patagonia R1 Air Hoody. Size up one size if you’re between sizes.