So since my first mock up fit pretty well, I figured that was good enough and was going to just let it go. But then it occurred to me: the final corset will have cording, and I've never done cording. And since the cording will be near the bust, what if it shortened the bust so that the extra length I added disappears in the cording? So I decided a second mock-up was in order. I want my finished corset to be a single layer of coutil topped with a layer of silk duponi, with external bone casings. The cording I can sew between the silk and the coutil, but for the mock-up I used a scrap piece of duck. At first the cording didn't look like anything that would give support, but when I finished, Wow. Here's a look at the corded mock-up:
To compare, this is the same seam on the non-corded version:
See how the corded version stands at attention, while the basic version just wrinkles down on itself? Color me impressed. The fit overall was better this time:
Update: I ripped out the bust seams and sewed them with less of a curve. Much better.