I've hand quilted for years but have never been concerned about whether the quilting shows on the back. I usually use a light backing and off white thread. I'm looking for texture on the quilt rather than seeing the stitches.
But I agree that a high contrast thread should show up. Hand quilting takes a lot of practice. You should see the first quilt I did 30 years ago. It is really pathetic, but I love it and use it all the time.