Building a sustainable Japanese fleet without naval treaties

How might Imperial Japan build its navy from 1919 without naval-treaty limits?

Keep the Nagato and Amagi groups, build balanced cruiser families and modest carriers, and avoid a construction surge large enough to wreck the Japanese economy.

The proposed Japanese program retains the Nagatos and completes the Amagis while cutting other new capital ships to avoid exhausting the economy. The resulting fleet would have fewer battleships than desired but remain affordable through the postwar building surge. Two slightly enlarged successors to Hosho, tentatively around 18,000 tons, would begin the carrier expansion. Cruiser construction would favor more numerous, balanced hulls, including designs with eight 8-inch guns, nine 6-inch guns, and a smaller flotilla leader with eight 6-inch guns. Destroyer development would broadly continue along its existing course. With hindsight of the 1929 crash, two or three 20,000-25,000-ton carriers would be laid down early enough for their completion to be defended as a measure to preserve jobs. Tighter budgets would then shift attention toward reconstruction and lighter forces.