I cut open the front panel pieces and then separate the four panels by tearing out the basting stitches. The final pieces should be trimmed so that there is a uniform seam allowance on all sides. These lining pieces will be used as patterns to cut out the pieces of fashion fabric for the gown construction, so you want the seam allowance to be built-in and consistent.

This fitting took about one and a half hours but can take longer when first trying it.