Cute blocks - you could give this a bit of a modern twist and put a couple of wonky shaped borders on each with some fabrics that capture all the colors. Could we see pictures please of some of the other blocks? Doing this would certainly enlarge your blocks, I'd probably go close to 24" total on each - that would be roughly 3-1/2" on each side, but cut them wonky. You could mock up one more block and put in the center - 3 x 3. This would end up giving you roughly a 72 x 72 quilt. Will be fun to see what you come up with!