I too followed your original threads. I remember how much you stressed over it being perfect. I think it looks great. You should take to the person who shot down your idea at the fabric store just to show her it could be done, and not only could be done, but done WELL! Your son will love it.
As far as backing, if you are taking it to a LAQ most prefer the wide backs so it is all one piece. Make sure you thoroughly check out your LAQ (see samples of their work etc) so you know you will be happy with her (or his) work.