12 Pound Ultralight Challenge: Shelter

I have three options for shelter. I have a two person Eureka dome tent, a Nemo inflatable tent and a bivy.


ITEM OZ
Tent Stake Bag 0.4
Bivy Pole Bag 0.5
Eureka Pole Stuff Sack 0.5
Bivy Stuff Sack 0.7
Titanium Tent Stakes (4) 1.2
Eureka Stuff Sack 1.4
Alum Tent Stakes (4) 2
Titanium Tent Stakes (7) 2.1
Blue Tent Stakes 3.6
Nemo Pump 4.7
Nemo Stuff Sack 5.6
Bivy Poles 5.9
Nemo Footprint 10.6
Eureka Rain Fly 14.3
Bivy 17.5
Eureka Poles 18.0
Eureka Tent (Main) 53.5
Nemo Tent 77.99

For either the Eureka Tent or the Nemo Tent, I'd take seven titanium stakes. I also wouldn't bring a footprint for either tent. Total weight:
Eureka (total): 90.2
Nemo (total): 84.79

If I took either of those tents, I'd split the weight in half. The Nemo tent cannot be split, so my tent partner and I would have to divvy up some other gear to get everything even. Carrying Weight:
Eureka: 45.1
Nemo: 42.4

The Nemo is the choice for a two person tent. In addition to being a few ounces lighter, it is the coolest tent every made with lots of additional room.

I also have a bivy sack. For the Bivy I would take four titanium tent stakes.
Bivy (Total): 25.8

And the Bivy is the clear winner with a savings of 16.6 ounces over carrying weight of my lightest two person tent.

To Recap:
Sleeping System Total Weight: 42.6 (22.19%)
Shelter Weight: 25.8 (13.44%)
Total Weight So Far: 68.4 (35.63%)
Remaining Weight: 123.6 (64.38%)

UPDATE: Tonight I will be sleeping in the bivy with my sleeping bag liner and an emergency blanket. It is supposed to be in the 40's with rain, so if I stay warm tonight, it is a go. Clothing wise I'm going to start with as little as possible on and will dress myself through the night as needed UNTIL I reach the point where my additional clothing negate the weight savings of leaving my bag at home. Should that occur, I will go in my house and crawl into my warm bed with my wife. I will not give up though, as I will try again when the daily low temperatures go up by about ten degrees.