Thanks, everyone, for the input! I can see I wasn't entirely clear in my post.... I just have the plates, no top. My mom has another quilt that she had someone put together for her - they just had the blocks and the contemporary quilter put them on muslin, which is where I got that idea. The plates have so many different print fabrics I thought I would need to use a solid color to applique them on. The plates also already have yellow centers that have been hand-stitched in. So... after reading the posts here, I'm thinking about compiling your suggestions and appliqueing the plates on to the muslin, then removing the original basting stitches before doing the quilting with batting and backing. Or, I could use the musline for the backing and use another solid color for the top itself.