This top-down shawl pattern was designed to use two similar laceweight yarns held together. If you can get gauge with one strand of fingering weight, you’ll only need 875 yards. Otherwise, it’s 875 yards of laceweight x 2.
This pattern is a great way to use up the laceweight you thought you’d use but turns out to be too fine to knit enjoyably. Or you can create a new color, by blending two different colors of yarn together. Similar colors, like the ones used here, deepen the look of the color. Two very different colors will give a marled effect.