why not?
because it's stupid. Yamato was as big you can get a battleship. Montana was at the limit and thus was one of the many reason they was not build. (and also they will come to late to be useful)
How do I scale it back any ways?
by using a program called Photoshop or Gimp or MSpaint.
For more refs on Montana:
viewtopic.php?f=17&t=2588