According to her website, her yarn is a 5ply light worsted (or a DK) weight yarn @ 10 WPI.
If this is true, then each single of a 5ply would have to be 50 WPI...in otherwords, froghair. And I just don't like spinning that fine. So, I thought to change it to a 3ply yarn, so that the singles would only need to be about 30 WPI each.
The yardage required is 822 - 1233 yards (depending on size). My current grist is about 55 yards / ounce, which would require that I have 16 ounces for the barest minimum yardage
822 yards / (55 yards/oz) = ~ 14 ounces.
Here's one of the skeins that I've plied thus far. It's lovely, air, and oh-so-soft!