Getting a bit fed up with tents right now… call me when a lightweight bathtub floor is more than 3 inches before mesh takes over the walls. My experience is that these tent styles just plain don't work on soft ground in the sustained rains I seem to encounter nearly every night when backpacking — regardless of site selection and awning protection. Pooling water on a floored shelter does me no good when my next layer of protection is a permeable sleeping bag. Anyway, that's another rant for another day and an unfortunate consequence of my backpacking region.
With that out of the way, I would like to announce that I plan on switching to bivy sleeping in the near future. My shelter selection looks to be a floorless 'mid to hold up to sub-alpine snow in the winter, and to be able to provide protection above treeline for 3-season use.
The MLD DuoMid intrigues me right now, but I'm not sure how well it would stand up in strong winds above treeline during 3-season use. Can any 'mid users comment on this? I would likely order the sinylon version, since Cuben is out of my price range, and I'm not completely sold on Spinnaker — $80 extra for a mere 3oz saving doesn't help either.
For the bivy, I'm torn between the MLD Ultralight and the TG Ptarmigan. I would request a custom, side-zip Ptarmigan if I ordered one; but I have no idea what the weight penalty would be. The TG bivy options seem like they can be much more airy for summer use (it's unlikely that you'd find me sleeping on bare ground without full bug protection — even in the summer).
Above is what I am currently considering, so, of course, other recommendations are greatly appreciated.
I currently use a 17oz tent, so I'm hoping to find a bivy/shelter combo under 23 oz (I can make up the 6 oz difference with a lighter WM bag in the future). I'm also 6'1", ~160lbs, and my primary backpacking trips are currently 4-season, 3,000-6,000 ft elevation hikes in the Southeast.

