We Call Them Pirates

[whoresonthehill.livejournal.com]

I just sorta finished the hat from Hello Yarn, We Call Them Pirates. I'm now supposed to pick up the stitches at the bottom, switch to a needle size that's 2 sizes smaller (1, instead of 3) and knit a couple inches, then sew inside the hat. Basically, knit a band for a lining. However, I had to use 2s to keep the hat from getting too big, and I don't have anything smaller. Should I use a thinner yarn on my 2s, or should I just try to knit the lining at the same gauge? I'm so proud of myself so I really don't want to screw it up, but the hat sorta needs a lining to keep the bottom from rolling up.