I use a lot of WOW fabrics for backings and never have a show through. Even when using black or dark reds. I do buy my WOW 108" -120" wide made for quilt backing. This could be the difference. I usually use a W&N batting to and that too can make a difference. I am just finishing up a quilt that uses a Hobbs 80-20% and with the many bold colors in this quilt I am getting no show through or see through problems. These two factors combined make the difference. To resolve without changing one of these elements I would think about adding additional batting since it is so thin or taking the added expense and replace the backing to something heavier. Try a sampling first before spending a great deal of money.