I've decided to just continue on with the Nettie version I have on the needles. I think it's going to be a bit small for a standard shopping bag, but I'm sure I can use it for produce or something. Plus it's like a swatch. I'll be able to see how much the stitches stretch so I will know if I need to up the needles size or add some YOs.
Currently, it's standard dishcloth cotton on size 10.5 (US) (6.5mm) dpns. I'm also going to switch to circulars just to get the hang of those. It looks a bit tighter than I was hoping (and taking longer), but we'll see how it works once it's stretched.
I know I only have about 3 readers, but if you would be interested in a shopping bag KAL, hit me in the comments and we'll see what we can do.