Sizing floating dry docks for supercarriers

Would a superpower Royal Navy need many 300,000-ton floating dry docks?

No; docks around 150,000 tons would be more credible if the largest carriers displaced about 120,000 tons.

A fleet of scores of 300,000-ton floating dry docks would be disproportionate. For a hypothetical 120,000-ton carrier, roughly 150,000 tons of dock capacity would accommodate the ship and provide a useful safety margin. Dock capacity should follow the largest vessel that actually needs maintenance rather than an arbitrary grand total. Support assets are sized around realistic fleet demand.