Alex -
-The "shouldn't go over .030" is something that people have just learned to say.
The statement usually applies to 427 blocks. Not always. Depends on the thickness of the cylinder walls.
A 428 block that was recently sonic checked by a good friend had thicker cylinder walls after it had been bored .060 then a standard bore 427 SO that was checked at the same time!....
I don't know the answer to your question - sorry.