A big thank you to Gayle for coming to the rescue with my thread request. Progress has come to a halt now as I'm all out of thread.
If anyone else has this chart in their stash waiting to be stitched, I think it well underestimates the amount of thread needed. It was supposed to take 12 yards on 32 count, but I have already been through 20 yards. Make sure you have plenty of extra thread before you start, especially if your thread is not easy to lay your hands on.