Would the proposed 12,000-ton cruisers automatically be heavy cruisers?
Short answerNo; the heavy-cruiser category did not yet exist in the treaty, and the proposed ships developed from the large-light-cruiser and scouting tradition.
NotesTreaty terminology matters because later labels can hide the original design logic. Washington divided capital ships, carriers, and other vessels without creating the London treaty's heavy- and light-cruiser categories. The Hawkins class supplied one of the practical reference points for the negotiations. A larger reconnaissance cruiser could therefore carry heavier guns without being conceived through the later heavy-cruiser framework.