Hi There
Some really good advice from the posts above.
Your Bow is more than adequate - dont know what your draw length is but on an ave. 29" draw you are probably shooting at about 270 - 280 fps with about 69lb KE - which is more than ample for any South African Plains Game.
Hunting from a blind can be far more productive than walk and stalk / spot and stalk - as a lot of Farms are typcal South African scrubland with thornbush ( and more thornbush, and more thornbush ! ) which doesnt lend itself to great cover - a further problem, s that there are just so many eyes in the South African bush - sound silly, but its a fact !
Another concern you may wish to consider is that there are not many farms that allow BOTH Rifle and Bow hunting on the same farm. If you do find a farm that allows both, you will probably find the animals to be a lot more spooky - which will compound your problems with the Bow.
Just be cautious on Impala and Warthog - these guys are " walking neurotics " and are more than likely to string jump you on any shots over 25 yds - a fast / quiet bow being the answer here - a word of caution here - dont try 50/50 shots on them ! Wildebeest are also extremely tough - be sure of your shot placement before you release - many Wildebeest are lost with the shot being too high due to the illusion of lower 1/3 on a Wildebeest due to the unusual humpback. Dont let this put you off - if you place the arrow on the shoulder, on a side on shot, you will be just fine - they are also a bit too bulky to string jump you.
Enjoy your hunt in Africa ! let us know how it goes and please share some photos with us !
If you need any assistance / advice, dont hesitate to drop us a line.