LYS owner looked at the swatches on #4 and #5 needles, and pointed out that #4s were too small -- the swatch curled badly. So I will just have to accept the ~15% pattern elongation on the #5s. This is why books are good, but experienced knitters are better.
Yesterday, I measured the swatch area, then I put stitch markers at the beginning and end of the swatch, and pulled it out and measured the length -- 125 in for a 13 by 13 swatch. The ovals are about 70 by 35 stitches, or about 1925 stitches total. For 14 ovals, this turns out to be only about 3 skeins of yarn (Jamieson's is 170 yds). I've put in an order for the Jamieson's DK: 3 skeins of 726 Prussian Blue, and 2 of 187 Sunset. I am excited about getting the yarn in!