I finished this on Canada Day and got it blocked last night, running the blocking wires through the sides of the squares and at the halfway point of each square.
Final measurement? 54" x 25". Not bad for 100g of cobweb weight yarn (Noro Sekku).There was a bit left over so I'm guessing I used less than 400 of the 420 metres in the ball.
I recommend you do an entrelac piece before you try this pattern - like Criminy Jickets' 'garterlac' washcloth. The Dianna pattern states that it does not explain entrelac technique and to use other sources for that. I found that especially true when I went to do the final row of triangles along the long edge before casting off. I also suggest you make the k2tog stitches on the edge quite loose as you are going to want to be able the stretch that edge quite a lot when you block it.
It was a bit tedious to knit but I so love the result, I'm all geeked up to do another one (erm, maybe I should finish the other one I have underway?). This pattern is perfect for any yarn that has big bands of colour, particularly ones that change gradually from one to the next, like any Noro yarn or Zauberball.