I love slip stitch patterns, they make it look like I can really knit! You should know, though, that I always buy lots more yarn than I need. So please do take my recommendation with a grain of salt. I usually order at least 50% more yarn when I think I might use a slip-stitch pattern, up to twice as much if I can get a good deal and love the yarn. I split it into however many colors I plan on using and add an extra ball or two in the color I`ll be using for the cuffs, collar, etc. Some slip stitch patterns don`t divide the colors evenly, so bear in mind the rough percentage of each that seems to be used. Slipped stitches use up yarn, but they use less than regular stitches. Hope this works for you, or, better yet, maybe someone else will have a more precise method. Good luck.