The Golite sil is heavier than the standard 1.1 oz (1.3 oz with silicone treatment) sil that you see most of the time. The Golite sil is a 30d 1.76 oz/yd fabric. I have their UL poncho/tarp than is made from that sil and it is heavier than any other sil that I have used. It's really nice but I don't think I would try and make a really big tarp out of it because it would be heavy.
“Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it."