Honestly, the best solution for NA is to make unrepresented bulls have more calves, bulls that have been proven in natural mating like Maclean, Sdudla, and Tendaji should be used to the fullest extent there is no reason for Maclean to leave DAK as of now, Tendaji would benefit from leaving Dallas and heading to San Deigo and Sdudla could be moved to Omaha though at 10 they be at capacity, while bulls like Bulwagi, Ali and now Titan that are proven through AI should have the opportunity to have calves through that method though it is much more difficult to get a pregnancy through AI. Even bulls from the Africam Safari in Puebla houses three bulls Grande, Mediano and Chico one of them could move to the US as well as bringing in Tutume and Jeannot from Canada to the US as well.
Another alternative is to go the NA Asian elephant population route instead of importing mother-daughter pairings NA could focus on bringing surplus bulls from Europe and sending sons sired by Jackson and Mabu to Europe. Several bulls could be imported to NA like Tuluba, Martin, Noah, and Janu, and in return, NA could send Tsavo, Ingadze, and Macembe to Europe.