Why an unfinished Admiral makes a better carrier conversion

Would converting an Admiral-class battlecruiser have produced a better carrier than converting Courageous or Glorious?

Yes; converting an unfinished Admiral would allow a cleaner Lexington-style redesign without rebuilding a worn completed hull.

A conversion made before the original warship is complete can remove armor, guns, and machinery choices without undoing years of service wear. Lexington and Saratoga benefited because their carrier transformation occurred while the hulls were still being built. Courageous, Glorious, and Furious had to carry the strains, twists, and compromises of completed ships into their conversions. An unfinished Admiral-class hull was therefore Britain's better route to a large carrier, while treaty conversion allowances explain why the historical alternatives became attractive.