My advice is to use the heaviest bullets that Your rifle can shoot accurately. For the tough African species You will need as much as possible sectional density for deep penetration. I guess You are talking of a trip to Namibia and I can tell You that this is a country with lots of wind blowing and a heavier bullet will not be blown out of path as much as the lighter ones. Don`t be fooled by trajectory charts, rather try to get close and enjoy real hunting !

Kalunga