Usually I begin with a muslin, and then make adjustments in it, tossing it out when I have determined the changes. In this case, I just made the bodice length, for fit.
Then onto the fabric I might actually wear. This ancient piece of faux indigo was the right amount, and so I began cutting. Unfortunately I didn't have enough for the long neck facing and had to find another fabric for that. No matter, it hardly shows.
Now that I have determined the fit and decided the length could better work shorter, I am ready to start getting creative.