Hi and welcome from Texas. Glad you decided to join us. No help on your design board question, as I don't have one. I know several have discussed using flannel backed table cloths or flannel covered boards. I saw a small one the other day at Hobby Lobby that was probably 24x36" that was flannel on one side and cork on the other. As for color combos, I don't think there's any right or wrong, just what pleases you. I've seen some color combos here that I would never have thought to put together, but they worked! So, I guess just whatever floats your boat is good! Happy quilting!