I'm creating custom blocks of text. It seems that the layout for the pages when it is displayed is Center-center then cernter-right, then center-left.

Is there a way to have it set how I want it:

center-center
center-center
center-right
center-center
center-left
center-center

Yes you can do this with theme.html.

you can set it how you like, but i believe using more than once will display the same content.

Easy answer: NO

Lots of coding answer: Probably

As I believe what you want is something like this:

block(00) -> position:center-center
block(01) -> position:center-center
block(02) -> position:center-right
block(03) -> position:center-center
block(04) -> position:center-left
block(05) -> position:center-center

You would need to be able to controle blocks by their id, and I'm not sure how to do this....

Another issue is, that you want center-center blocks to once display with width=100%, and in another case with width<100%, which makes this idea a hell of a job...IOW, don't try this, but come up with another solution for your display/design desires.