I finally got around to taking some pics of my silnylon tarp.
1.1 oz Silnylon
12' ridge line
~10' wide at the widest point
Weighs 20.4 oz (includes tarp, guy lines, 6 x tarp tensioners, seam sealing and stuff sack)
7/8 grosgrain on edges
reinforments are made from a really heavy WPB Supplex
I made the tensioners on the ridge line from bungie cord instead or latex tubing. They work well.
Packs down pretty smal for such a large tarp: