I measured the bottom and shell, and the fit seems manageable as the quarters are attached, with inside corner to insider corner of the panel #4 at the top and inside corner to insider corner of the flat at the bottom. My #4 panel extends about a quarter inch beyond the quarter panel on the right (pictured above) and about an eight of an inch on the left. Removing this excess #4 with a sander after gluing the quarters doesn’t seem to be a problem, so I’ll glue the quarters this afternoon if I don’t hear more from the forum.