If you are trying to get Latinas to go Black, the easiest nationalities are definitely Colombian and Brazilian since those countries already have sizeable Black populations. Peruvians and Ecuadorians fall somewhere in between. Mexicans, Central Americans, and Chileans/Argentinians are the most challenging since those countries have much smaller Black populations (or none at all) and hence the idea is more alien to them. But they are also the most rewarding since it is not nearly as common and the kink/taboo factor is amplified.