Sorry for the confusion, not my intention. Started the thread saying this will be my third long distance hike and that i thru hiked in 99. The "Ultra light hikers forum" on whiteblaze is the wrong place to discuss and compare lightweight gear for hiking the AT? On my 99 hike I started mid may, and never had weather under 40 in that spring. April weather will be a new experience.
For a tarp, I think 9' is too short, 9.5' just long enough for my 5'11 frame, and 10' more reasonable when a light weight material is available. Also if the tarp is longer on the ridgeline than the sides, then the effective length is less than ridgeline length. If i was one of the taller hikers on the trail, even 10' might be too short. Stomach sleepers will also need a bit more length and side sleepers a bit less length. I am a side sleeper so that helps.
I use down tek because it was the default choice. No other reason.