Couronne Bordelaise

This is my first time attempting the couronne Bordelaise. I followed the instructions given by Susan at Wild Yeast Blog, using her Norwich Sourdough recipe as well, though I scaled the recipe down by 25% to produce two (roughly) 750 gram loaves. I did a test run two days ago, which turned out pretty well, though I had some problems with execution. I rolled the center disk out too much, and that piece didn't separate to produce the "crown" effect. The first of the two I baked this morning similarly failed to crown thoroughly.