The solid centers are screaming for a recognizable shape like a star or a fan (I think a fan would go with the girly/flowery color choices well and make it more victorian looking). I saw where a lady had hand quilted circles over her pinwheels and it gave them a nice sense of movement. I think a simple scallop around the edges would also give it flair without being as hard as the feather motif. Everything else would just be in the ditch so as not to take away from the softness created with the other ideas. I love cross-hatching but it would be too sharp with the other curves. Just my two cents! Good luck and let us know what you decide.