I'm going to keep my eye on this thread. I was wondering the same thing, "can he retrofit the beak".
I'm not sure which direction to go.
I have the door as well, and used it for the first time. It works very well so far (no wind), and looks good. I left the top of mine undone, and sort of folded, flopped it over, so that the top was open for venting.
I don't think I pitched it properly/full height, so with the door attached there was no mesh showing/fully enclosed and I built a snow wall around the sides, so was worried about ventilation.
Slept pretty well though. No wind, -2*C:


Now what I'm wondering about is the floor once you have a beak. You wouldn't need to move the floor around the avoid spray, and could sleep two small people in there in pinch.
Another advantage of the door, besides having the option to not take it, is that you can adjust the height of it and coverage depending on conditions and venting/view desireability.
I"m using the tyvek, and with duct tape, fashioned a bathtub floor. The head and foot end stay up, but the sides sort of flop over.
No big deal, but I'm kind of anal and lazy.
Wondering if the Cuben zpacks floor would be worth it?
Maybe with little loops on the mesh/corners to tie the floor corners to hold up bathtub shape. Not even sure if this would work.
Would having it sewn in be much of a weight savings (cutting out mesh bottom)?
Of course all this makes the shelter a lot more expensive, and probably heavier.
I don't know. Works pretty good as is.