Had some of this to play with, and made a few dry bags. It is noticeably more fragile than the 0.5 oz fabric, and ripped quite easily. I concluded, as Joe from Z packs suggested, that 0.5 was fine for a tarp, 0.75 as better for dry bags, and that 0.35 might be useable for very light tarp applications.
It sits,whilst I plan something worthwhile from it!
A