I think all these flutes are beautiful. Love the color variations.
Last year a man came into our gallery (an off the grid hippy type) with a clay flute he had made. He used a local natural clay known as blue goo which is low fire. He make the flutes and essentially fired them in a campfire. They clay was not refined and being low fired had low shrinkage. That enabled him to tune them while greenware. Gotta say they had the most beautiful sound. Really spot on.
Maybe paper clay would help you with less shrinkage and better tuning. But others are right - these are not for classic orchestras but for one's own playing. Nice stuff.