There's a fascinating study done on Swedish elections over the years - Gender Quotas and the Crisis of the Mediocre Man
The title sums up the paper well .....says have some quotas and the mediocre men disappear .......but also raised the overall competence of those remaining
One conclusion was the higher the competence of its leaders, the more likely a party was to win an election. Mate Jacinda should portray Bill as wet behind the years and useless and casually mention the concept of mediocre men (seeing Nats are likely to have the lowest proportion of females in their caucus)