I just got my 7/64 amsteel on Thursday and immediately made my 2 whoopie slings and my structural ridgeline whoopie... 50' was perfect with about 8' or so left over for trying a nacrabiener or other such things.
This stuff is *SLICK*! I was worried about making the slings, not sure how it would all work out. Once you start working with it the procedure becomes quite obvious. I got my two slings identical in length and loop size on the first shot!
Definitely worth the wait of ordering online, which I typically hate -- always seem to run into a hassle during delivery.