This collar will sit on a somewhat tulip shaped coat. The collar will soften the appearance of the otherwise strong lines. I have come up with two solutions that might work. In the picture of the front, you can see both. While I am doing other things, I look and think of what feels most correct. The pictures from the sides are showing the silhouette of the two options. Should this be so difficult? Exactly how big is the difference?
How the collar should be closed will be significant. Buttons and buttonholes will be too bulky, small button and a loop might work, press studs might work if the factory can stitch them in well enough (efficiency and price are important factors), I'm afraid hooks might get caught in the fabric and pull out threads, ribbons might be troublesome and might also disrupt the lines in the collar's folds... Hm, hm, hm.....