Asking this question implies to me that you are not accustomed to hunting with a scope. If that is the case, then trying to get accustomed to a scope on an expensive African hunt makes no sense. If you are thinking scope versus receiver sight, then as far as aiming preciseness is ocncerned you will not sacrifice much by using a receiver sight. However, there are more issues involved than aiming preciseness. You may be called upon to shoot in low light conditions, where a receiver sight or open sight would be next to worthless. You may be called upon to shoot at an animal which is clearly visible to you through binoculars, but which blends into the scenery with the naked eye.

Assuming you have time between now and your projected hunt, I would recommend that by all means you choose a scope, preferably a fixed power 4X or less. Then you need to practice with it. You can do this in your living room, by taking your (verified) unloaded rifle, holding it at the ready position, selecting a discrete object in the room (door knob, light switch) and raising the rifle to your shoulder until you are looking through the scope. If you practice enough, you will find that the crosshair of the scope comes to rest on the object you are looking at. When you have achieved this, you are ready to hunt with your scope, and need only range practice to perfect your technique.

I have heard horror stories from professional hunters whose clients could not find a record book kudu in the scope, although it was standing in the open, 60 yards away. The same with a leopard on a bait tree 40 yards away. In either case, the client would have been better off with metallic sights, but that need not be the case.

I approached African hunting with years of varmint hunting in my background, which involved locating a relatively tiny object like a crow or groundhog two to three hundred yards away in my 8X to 10X scope and lining up and executing the shot before the elusive game disappeared. I recommend this form of hunting highly as a preparation for an African hunt. If this is not an option, then long hours at the range will pay rewarding dividends.