Are you PP the arc sections? If so I would pin an arc section to next section with the paper attached. See if it looks like it's going to fit first. I think if you remove the paper the arcs may stretched due to the bias edge. If they are short, stretching could be a good thing (in which case I would remove the paper). If they fit just right, I would sew them together without removing the paper. I've never been brave enough to do one, so I'm not much help.