I think the 11s may be too large. But knit a sample and see how the gauge compares, you might get the same, the only thing is it'll be a looser knit. That may be okay with you. See how many sts per inch you get, then multiply it by the measurement the stitches in the pattern use. If it's too large, you can cut down the stitch number by increments of 2 (because of the ribbing pattern).
sue- knitting heretic