I also think they both would work, but like the one on the right better.
Here's a small one I made with about 2.25 yards. I think I actually cut the borders first and then used the rest for the quilt. I used 4" triangles. The OBW portion is about 24X36, and I think I only had about 30 some hexagons... I agree the color flow isn't as dramatic as it could have been, but I was just trying the technique. You could also use smaller trianges. They would isolate the individual colors better and give you a wider range.
http://www.quiltingboard.com/picture...w-t105995.html