S to S "sil" bag material & tarp questions!

[Suzyqhoo]

So I have an XXS orange (dunno if that matters a hill o' beans) really, really lightweight silnylon drawstring Sea to Summit brand bag.

Question #1: Does anyone know what weight this silnylon is? I scored about 14 yards of the Wally World version of this (Sea to Summit bag) material.

Question #2: Is this weight what everyone makes their hammocking tarps out of?

I went back to the same Wal-mart yesterday (one month after the initial score) to see if they had any more silnylon left...and lo and behold, I got some more, but it is heavier.

I am jumping up and down ready to make one of Black Knight's Black Cat tarps (Mom sews and has agreed to help! Lucky me!)

Thanks for any insight you can provide!

Suz