An attractive paper fleet may exceed what Australia could crew and maintain. Six or seven Hobarts would provide a more useful minimum, while eight could form two four-ship squadrons split between the coasts. That structure normally leaves ships available locally while another can deploy farther forward. Twelve would impose budget and personnel burdens beyond the likely sustaining base, whereas a longer run of six to eight also improves production efficiency and career depth.
Notable Point · 1:57:30-1:59:24
A sustainable Hobart-class force
The proposed answer is not a dozen destroyers but roughly six to eight: enough for availability on both coasts without exceeding Australia's sustaining capacity.