You are close on this.
Most 12" rough toilets have 3/4" behind the toilet, thus they will mount with 11.25" from the wall, measured from the wall to the center of the drain.
Sometimes you can move the bolts out that extra 1/4" and install the standard 12" toilet anyway.
If not, the other option is the 10" toilet.
TOTO now has a 10" dual flush at the factory.
I'm bringing some here for the Seattle area.