Even the larger fleet does not make Operation Catherine practical

How many more battleships would Britain need before Operation Catherine became acceptable?

Far more than the no-pause scenario provides immediately; even five KGVs would need the Lion class and additional replacements behind them before Britain could risk three conversions.

Operation Catherine would effectively remove several battleships from normal fleet use and send them into an exceptionally hazardous theater. Completing the five KGVs improves British depth, but it does not make three disposable capital ships easy to spare. The Lion class and further replacements would also need to be securely on the way before the Admiralty could absorb that risk. Catherine remains one of Churchill's less workable ideas even in this more favorable construction timeline.