Finally had a chance to pitch it during the daytime. The "half-door" flaps seem to work as well as I had hoped and cover the ends of my hammock nicely. Even reposing on a slight diagonal there is still 3-6 inches between feet/head and the half door flaps, even with the tarp pitched fairly high. I believe that if it were pitched low and closer to the hammock, as some of you suggested, it would make as near an impermeable shelter as could be expected from a hammock setup (except maybe the larger winter tarps with full doors I suppose). Whole setup including tarp, hammock,tree straps, and stakes is ~2.5lbs.

I'm extremely satisfied with my design and am trying to come up with a name for it now

side:20150805_110004.jpg
end1:20150805_110025.jpg
end2: 20150805_105956.jpg
inside: 20150805_110012.jpg
head: 20150805_105903.jpg
foot: 20150805_105845.jpg
flaps up: 20150805_111207.jpg

Going to field test it this weekend, but the chance of rain is minimal.