I suppose it is a matter of taste. I got two sets of skeins from a yarn shop, with the understanding I'd make them up a sample bag for the store, and I'd get to keep the other set.
The bag I made for them made me so sad! Such beautiful yarn, and such a blah finished product, IMHO.
But when I posted pictures elsewhere, other people really liked it. Go figure.
I never felted up the yarn for me, I made a hat and scarf instead. Very luxurious!
So I'd say, swatch first, both double strand and single strand. It is such lovely stuff, you want to be sure before it goes in the washer.