It isn't balanced yet...you have the right idea, but try moving the blocks around some more,
For instance try for all the same dark color blocks on the four corners and one in the center. Then put the four light blocks in the center of each of the sides...just for one idea.
um...think of the spots on a playing card as an example of balance or being symetrical. J
edit add on:
You are getting the idea! I like the last photos best! My congratulations on very beautiful blocks and color choice!
I am sure that it will turn out beautifully!