You are doing a good job. I'd say keep the other prints for another project.
You already have 2 blues, green, yellow and red. IMHO, it would be a good idea to use those in the border(s). You could have simple strips, 4 patches on point with a plain outer strip, get extreme and piece trains and or tracks all around. Now that I think of it, yes, tracks with mitered corners and another border or 2 beyond. Simply make one border pair wider than the other pair to make the difference in width.