Kitchener Stitch is a method of weaving two open edges of knitting together that when joined, leaves no seam and the stitches meld into one another. Well Marjorie when selecting a yarn for Grace's sock patterns I first recommend Socka 50. Socka 50 is manufactured by Stahl, and is imported from Germany Its nylon content is a suitable yarn for sock durability. Socka 50 is available in a wide variety of colors, and is considered a leader in the manufacturing of sock yarn. It is best to work a yarn that has a similar gauge and fiber as that of the recommended yarn.
Substitutions are easy.
The labels tell you a lot. You will be able to summarize by the label if the yarn will work with your pattern. Take a test gauge with the substituted yarn. Alter the needle sizes when necessary to obtain the gauge desired. That's a great question Judith , The leg portion of the sock is knitted on straight needles, however the foot portion to the toe is done in the round on double pointed needles.