I decided to just go with one border, in the red tone on tone, as you can see, but I was worried that the red might be a bit overpowering, so I thought it'd be a good idea to put another, smaller hexagon block in each corner.
When I had that bright idea, I didn't think it through very well. How do you turn a 5" hexagon into a 6" square? (The answer is :with difficulty and quite a bit of waste of fabric by the way.) After several false attempts, I did it by adding oversized 60 degree triangles to four sides, then cutting them down to a 6" width and adding strips to the other two sides. It may have taken me a whole day, and a lot of fabric to do it, but I think it was well worth it.
Now all I have to do is decide how to quilt it. Any suggestions anyone?