You are about to read the saddest story ever told.
(As sad as hoop-skirt stories go anyway.
They were completely fine with me going around an trying to turn their things into a circle. Yellow tongue seemed very promising if I was to make a bustle skirt, but couldn't hold itself without buckling. However, I will have to keep that one in mind.
The best I could find was plasterboard jointer. It made such a clean circle when stuck around without any effort in my half. The downside (or the only downside I could see for now) was that it needed duct tape to hold it together, making it seem unprofessional. That didn't deter me - I was the only one to know.
I did this outside, as my studio had too many things in the way. I probably could have done it all inside, but it wouldn't have fitted quite as well. Unless I moved my work table outside, but doing this outside was much easier.