Regarding Gauge: “Any worsted-weight wool should yield the correct proportions, no matter your tension. The final size will be determined during felting.” (This quote is directly from the pattern, and can be found on page 133 of Felt It!)

The pattern calls for 3 colors of yarn--220 yards of each color (One skein of Cascade per color), but more than half of each was left over.

A quick summary of how the placemat is worked:
“You create the placemat’s circle shape on straight needles by decreasing at regular intervals throughout the pattern. When the piece is done, you seam it along the side edge to complete the circle shape. Use a cable cast on to start.” (page 133 of Felt It!)