let the sashing tell the story... ignore the blocks and choose a color palette.... purple to mauve to lavendar to yellow, or forest to deep green, to olive to sage... whatever your favorite color range is. Then put the darkest sashing on the bottom row, move up one row and one shade in your palette.... if the blocks are only 5" you can use a sashing that's 4" and overwhelm at the same time you're creating the color spread that's lovely all by itself... the blocks could be in the center, in the corner, off center but in the same position in every square.... anything you do within a large frame will be set off and muted at the same time...