Re Dave's comment: "Show coverage when the door is open, say when cooking just outside the door. You will find with the duo you will be letting in a lot of snow/rain."
This "exposure" when the door is open would appear to be a characteristic shortcoming of any pyramid tarp.
The alphamid likely mitigates the rain/snow exposure of an open door a bit since its doorway is a nearly vertical wall rather than sloped. But even with the alphamid, even a tiny wind brings rain/snow through its open doorway.
I've wondered at times about the feasibility of a simple and easily deployed awning that could extend just a bit of coverage over the door of pyramid-style shelters -- at least when the door is open and rain/snow is falling. An awning that affords even partial coverage (say, for the top half or so of the open door) might help to deflect a good bit of percepitation.
Perhaps an awning could be fashioned with a peice of wedge-shaped material (cuben for lighest weight?) that has one of its points attachable at (or somewhere below) the peak of the pyramid, with the other two points of the wedge pulled taut (almost on a horizontal) to extend a few feet of protection over the open doorway -- maybe by means of guylines running down to the front stakes from the end of very light weight rods (carbon fiber?) that are secured (somehow) to stick out at each side of the doorway?
Upon pondering this problem a little more, seems like the pyramid-style shelter would really benefit from a tunnel entrance, quasi-igloo-like to eliminate entirely the issue of exposure to wind-driven elements when entering or exiting the shelter. This solution was part of the design for one of North Face's old A-frame tents ("The Mountain Tent" from back in the 60's) which had a tunnel entry set into one wall for foul weather use and with a panel door set in the opposite wall for fair weather. A vent sleeve was also provided above the tunnel entrance for when the tent had both doors shut tight.
And if the roof of the tunnel entrance extended a few feet out from the pyramid -- bingo, a protected cooking porch.
Inquiring minds and wet heads would like to know.
But please, don't ask for a diagram.