Hi Andrew,
Thanks for the update.
Regarding the duplication of controls, there is a known problem with the designer that hasn't been fixed yet, but has a temporary workaround. You can track the problem here and the head entry with the workaround here.
Converting back and forth between Windows Forms and Visal WebGui is one of the goals in making Visual WebGui almost code compatible to Windows Forms, so I'm glad this helped when you had to change course.
Good luck with the Windows Forms project.
Palli