I knew the heavy, 7.1 oz linen canvas from Fabrics-store.com would stretch, so I made sure the opening in the back would be a little wider than on the pink stays. Also, after wearing the pink stays a few times, I realized I needed to cut down the armholes considerably. This project benefited directly from mistakes made on the pink stays.
They are also much more flexible, as I used the 1/4 inch wide cable ties for boning as opposed to the thicker ones on the pink stays. Really, I just need something to shape the bust for this set.
My one serious regret here is the binding. I used a cotton twill that in retrospect, I just too thick. I was worried about the bones poking through the binding if I used linen, but next time, I'm just using something thinner.
The first test-run for these stays will be the Midwinter Ball on January 31. Hopefully it works.