1. Which yarn do you think I should use to make the Firmaments Pi Shawl?

Which yarn do you think I should use to make the Firmaments Pi Shawl?   Whorled Peace Superfine Merino, 2500 yards in 8 oz Blue Moon Fiber Arts Laci in Valkyrie Extra Fine Merino 1750 yards in 8 oz Something else altogether (please leave a comment on the blog with your suggestion)