Thank you hildegard! I thought about using a few pieces of boning in the back, but was worried they might get bent when I pull the top on over my head. I am not familiar with flexible coil boning. Is this very different from regular boning?
It's way more comfortable! It bends with
you, instead of into
you. Apparently it's actually called spiral boning; it looks as if someone took a spring and squished it flat lengthways.
There are pics and a brief description on this page http://www.corsetkits.co.uk/page24.htm
I think you'd be able to find pre-cut and finished lengths at your local fabric store, but if not, the internets appear to have it for sale as well. Also, fun fact: you can google 'spiral boning' with safe search off, and only get corset-related results! And they say the internet is full of filth. Ha!
Hope that's useful- cheers!