Actually the question for American Battleships is, what will they do once the Treaty ends? Or once the building holiday is over, will the Americans feel overwhelmed by the sheer size and number of massive, high speed, 15 inch armed hulls in the world?
If so, would the United States attempt to get a new treaty signed to allow for larger guns, or more tonnage to compensate for there 14 inch gun fleet. I'd also assume they would scrap all 12 inch gun battleships as soon as they can to build new modern hulls. If 14 inch guns remain the American standard, then the job of the quartermasters and manufacturing will be much easier, as the entire fleet will be armed with 14 inch rounds (let us assume some of the refits modernize the 14"/45 cal. to 14"/50s to allow for the same rounds to be fired by all ships) The only two ships I see that being a problem on are New York and Texas, and I imagine someone was working on that. Or let them both age out just like the 12 inch battleships and replace them as well. This give all the ships AON armor.
So to assume all of that...lets see. That would allow for the following by roughly 1935:
Saratoga--------------35,000
Lexington-------------35,000
West Virginia---------32,600
Washington----------32,600
Maryland--------------32,600
Colorado--------------32,600
California--------------32,300
Tennessee------------32,300
Mississippi------------32,000
Idaho------------------32,000
New Mexico----------32,000
Arizona----------------31,400
Pennsylvania---------31,400
Oklahoma-------------27,500
Nevada----------------27,500
This leaves the United States with 161,235 tons to construct and refit with after Texas is retired. (This also allows for 6 treaty hulls to be built as of 1934)
That is 4 x 40,000 ton battleships, plus very little left over for refits. If one wanted to build to the maximum number of six hulls, the displacements would be rather low (26872.5 tons). Or the Americans could not build a ship (either earlier or later) and build bigger, but I think that no matter what, they will end up at least one hull short of their 21 ship maximum unless they design light weight battlecruisers, or seriously over armored, and undergunned battleships that are slow.
But that is just me.