I have heard of ground dwellers using their ponchos as tarps. I thought about making one 9'x9' either out of sil or tyvek. I would love the sil better, but it is hard for me to find, and I have TONS of tyvek.

Would this idea be worthwhile for hammocks?
What would be the best material all around?
Am I just wasting my time?

I plan on putting grommets on each corner and setting it up on the diagonal, tying the hood shut. Thanks