I've been working on this as well, off and on, and finally finished up Chart 2 last night. I'm going to skip Chart 3 - not crazy about cables in lace, especially with a pure silk yarn. Fortunately it should be pretty straightforward to match up Charts 2 and 4. I'm also going to repeat Chart 4, working it two times instead of one, and I'll probably do the same with Chart 5. This should make the shawl more of a Pi shawl. That was one of the things that threw me with this pattern - you're doubling stitches between charts until you complete Chart 4, but the number of rows in each chart do not follow the traditional doubling that you would see with a Pi shawl.
Pattern: Rosebuds A-Flying by Heatherly Walker modified to be a cape
Yarn: The Unique Sheep Marici Lace in Rosebud
Needle: US 3 (3.25 mm)