If you want it to show, use a contrast. The higher the contrast, the more the design (or in my case, the booboos) will show. The quilt on my frame...3 shades of purple (light to dark) and off white, the owner picked a soft green. You can see it, but it does not jump out at you.Love it!
If you just want the texture, match it to the top. I learn something from EVERY quilt I quilt...