My wizard control is now working in the Windows Forms designer, which is a great relief. What will happen when I actually try to run it is a different question and I'll probably have to get around to answering that shortly.
In the meantime, I am now reconstructing the twelve (!) pages of the old MFC wizard (not all of which execute on any particular path through the wizard) in the Windows Forms environment. This is an exercise in tedious sort-of-programming.
But it's progress.