Navies would spend carrier tonnage gradually

Would navies use their treaty tonnage immediately or save some for later?

They would mix the two. Battleship allowances would be used and renewed through replacement, while carrier construction would take years to absorb the available tonnage.

Capital-ship allowances would largely be used and renewed by replacing older hulls. Aircraft-carrier tonnage could be consumed more gradually as conversions and later designs entered service. Four Lexington conversions would not all be ready until roughly 1927-28, shortly before the next conference in 1930. The construction timetable itself therefore limits how quickly the larger allowance could become an operational carrier fleet.