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A thin cotton fabric for batting helps to hide the seam lines from the quilt top.
Or a heavier cotton print fabric for the backing may be able to do the same.
Maybe when you get the top done, audition some backings and see how they look in the light :D:D:D
I've got a top done and am planning on using a backing of marbled cotton blender, regular fabric strength. We tend to keep the AC around 72 or I can't sleep, the darned anti-estrogens have given me terminal hot flashes! My oncologist wants me to go till Sept, but can live with sooner if I can't sleep.
I use Quilter's Dream Request batting in summer quilts. It is very light and thin. It gives great body to the quilt and remains light.