I think sometimes a scrap quilt can look muddy if there is a wide variety of colors/tones. If you keep to one, like earth tones, or pastels or brights it will look wonderful. This particular pattern that you have chosen looks very good to use just about any color if you were to use one dark color (like black) on the one half of the HST.
Like Katier825 said, you can always tone down with a muslin or tone on tone.
Have fun!