I don't understand why Henry is opposed to a vestibule-granted that is a second hand statement, but if true, I don't understand the logic.

I tried winter camping in a SD Flashlight and with no vestibule in a storm, not a pleasant experience. The Hilleberg tunnel tents have huge vestibules and not that much added weight.

Now, a tunnel is a totally different design from a Tarptent, but if the goal is light weight, a reasonable alternative, from what I see online.

I briefly owned a Cloudburst, which I never used in the field, but did set up a couple of times. A winter version of that, with a big vestbule added to it, would seem to work for mild winter conditions.

Now, I may be wrong, but I would not expect a Tarptent to withstand the same weather as a four or five pole winter tent like a Mountain Tent, Trango or similar design.