Progress report
I now have all the hoopsteel casings attached to the hoop. They're 1 inch cotton twill tape. The hoop has been assembled as well as a bumpad to support the back. I tried on the skirt and it seems to have a good elliptical shape even before adding the steel. What's left: waistband, steels, finishing bits. I plan on doing a whole write-up of how I made this if it works out as I think it should because it was actually surprisingly easy to make up from scratch.