Afghan progress

I have finished all the pieces for my afghan, and now have to put them together.  I am having a problem deciding what color to whip them together with, but think I am going to end up using the ecru.  The instructions just say to whip stitch or slipstitch them together, but they are all different colors, so the stitching is going to stand out.  Usually I have outlined the pieces in one color before putting them together, so this is my first time with this issue.  I started crocheting them together, but didn't like the look of them, so I have taken them back apart and will  try whip stitching tomorrow.  So close, and yet sooooo far.