Building a 1950s fleet for an unknown missile future

How would you build 1950s warships if missiles are coming but no new ships can be built in the 1960s?

Build large capable ships with space and structural margin for later conversion, especially substantial six-inch cruisers.

Scale and internal margin matter more here than a narrowly optimized immediate design. Missile technology in the 1950s was not mature enough to define a single reliable future fit, so the ships still needed useful gun armament when completed. The proposal calls for substantial six-inch cruisers with enough volume and structural margin for later changes. A sudden end to new construction makes adaptability unusually valuable because conversion, rather than replacement, becomes the only path to a missile fleet.