I’ll just say upfront that I’m not a huge fan of using variegated thread in quilting. My quilting philosophy is that the quilting shouldn’t compete with the piecing, and variegated thread quite often has that effect.
With variegated threads it’s impossible to predict what color thread will show up on any part of the top, and the unpredictable color changes distract the eye from what should be a harmonious design.
That said, there are times when variegated thread works really well. See?
This is a great quilt top using a lot of Marcia Durse fabrics. Lots of different color blocks, all sashed with textural grays. We chose a thread with various colors of gray, and the water-drop circle pattern minimized any thread color changes.