Nonnie, sorry about the size issue, but as long as you're consistent, it won't matter if the block are 6 1/4" or 6 1/2"...what would be a bit more tricky would be to have them all different sizes, then it cold present more of a challenge to work with...your color choices and work is great!
Pssst...and don't forget, someone was very happy to pick up your work and take it home with them! :D