[COLOR="RoyalBlue"][B]Original pattern from Knitty:
Using MC and straight needles, CO 12 sts.
Rows 1-2: K all sts.
Row 3 [RS]: Join CC. Kfb, sl 2, k6, sl 2, k1. 13 sts.
Row 4 [WS]: Pfb, sl 2, p6, sl 2, p2. 14 sts.
Mmmm, if I were to attempt to make the pattern double I would probably do this.
Using MC and straight needles, CO 24 sts.
Rows 1-4: K all sts.
Row 5 [RS]: Join CC. Kfb, sl 2, k18, sl 2, kfb. 26 sts. (I would do a Kfb on each end just because kfb twice seems like it'd slant more on that one side)
Row 6 [WS]: Pfb, p1, sl 2, p 18, sl 2, p2. 27 sts.
Row 7 [RS]: Kfb, k1, sl 2, K18, sl 2, k3. 28 sts.
All in all, I think it's way more complicated to try to figure out how to double the pattern then just to adjust your needle size and yarn. Because doubling the pattern to me doesn't necessarily mean to double the instructions. So it's easier just to increase your yarn and needles.
Although I'm stubborn and I'd probably attempt to adjust the pattern. It's more complicated, you have to pay attention to the directions in the original.