I agree on the no-sashing vote. It's quite eye catching as it is, and if you wanted to build it out to something bigger, perhaps an offset wide border, probably with one of the darker colours (would want to audition to see what appeals to you there) would give it a really modern quilt look. I think if I was sashing them, again, I'd go with a more offset look rather than equal side-by-side setting and see how that looks. Look forward to seeing what you do end up doing ��!