So I've started a quilt that has some blocks all dark fabrics, some all light fabrics and some blocks are a mix of light and dark. I was using a cream Aurifil thread and when doing a few sample dark blocks noticed that the light thread was showing through on some of the seems. So it looks like I should use dark thread for the dark blocks instead of the cream. However, not sure what to use for the blocks that I will have a mix of the light and dark. What is best?