Sorry I’m really busy at work and I couldn’t work on the piece… Anyway you are right! I didn’t notice that rotation in the middle.
The process is the same that @DanielPiker suggested. To make the rounded and more precise shape I used the kangaroo component that pull points to the curve. So I was able to keep the shape close to the drawing.
I was thinking in those days that it’s maybe necessary to separete the mirrored shapes in the middle so to create a little gap and close this with a new mesh. The crease in those case won’t be created!
I didn’t try it but I think in this way, that in theory should work, I could have the problem when I will join everything together because I won’t have the naked vertices in the same position to join… It’s hard to explain I will show the problem when I can work on the model