It's an 8 - honestly I'm ridiculously pleased with it - so glad you like it too! I'll measure it tomorrow when it's light. There's loads of material - it's very swishy, but it doesn't feel too big if you know what I mean. I think it helps that it's a dark colour. It sits just right on the shoulders, around the neck etc. Might be worth ordering a 10 too, if you're bigger than me, just to compare (I would because the pale blue sold out so quickly)
I've never ordered from Justine Tabak - I read about her in a Guardian article on prairie dresses and just loved her stuff - it's very pricey though! And from someone who never wears dresses, I think having two is enough for the time being!
What does pit to pit mean?