Jim, you're right about the warmth. All I meant is that I be able to seal it off well enough that overventilation doesn't become a problem, which basically means the tarp needs to get close to or onto the ground. And don't worry, I won't try whatever system I chose up north first. I'll definitely be giving it a trial run atop local mountains where it gets more than windy enough to give a good test. I do have to wonder if you're right about tarp tents not being strong enough since they're getting hard to find. Henry has moved on. The Mountain Hardware Kiva appears to be gone. The Go-Lite Shangri-La is out of stock almost everywhere, including at Go-Lite.
While tarptents are used very successfully on the PCT, generally not in wintertime. if you want a wintertime tent that can take a snow load, and still stay reasonably light, go look at something like the Tarptent scarp
, or the Black Diamond Firstlight
I own a golite shangri-la 3 - and while it has become my typical winter tent, it is my typical winter tent in alberta where I am dealing with extreme cold, but not typically a large snow load. It would not be my first choice for somewhre I expected high wind and a lot of snow in winter. - that doesn't mean it won't do it - it's just not really optimal for such things. you'll end up having to beat snow off the sides a lot and having to be a bit careful.