Not only will I be making a corset with plastic boning, it will be crate strapping, at that. On the other hand, it will likely act more like baleen than steel does. I think I will use two strips per channel, however, as a single ply is too flexible for my taste. (Insert joke about liking things stiff here.) Some bones will still be steel: the bones that go in curved channels across the bust will be spiral steel and the bones along the lacing holes will be flat steel - if I have long enough ones. Otherwise, the lacing channel bones will be triple plies of the strapping.