Pomoxis has said it perfectly and I urge you to read his post again and again -starting with his first paragraph. I went to Africa in 1993 -and never got back there again. I stayed in Johannesburg while transiting to Zimbabwe. Coming out of Zim I again stayed overnight in Johannesburg. I didn't go down to Capetown and have regretted it ever since. Worse, I didn't go to Victoria Falls while in Zim -and I wasn't more than a hundred miles away. Yeah, Pomoxis is dead on. Be a tourist as well as a hunter.
Make sure that your safari shirts and pants are already laundry shrunk. (I was in the bush and all laundry was boiled in a big pot (yeah, like the cannibal pots in the cartoons)
Wear long sleeved shirts. You can always roll them up during the day. In early morning it might be chilly enough to want to cover your arms - but not so chilly as to need a jacket. ( Also if you are going to be in a malaria area then long sleeves in evening are giving the mosquitos less of a target area)
Try and carry a small camera in your shirt pocket. I carried a Leica Mini and it gave great pics -and I'm no camera nut. (A buddy of mine when we were kids said I needed a camera with a PHI button -"Push Here Idiot") You may want to weigh about bringing expensive binocs with you. After all, the PH is likely to have a pair and I'm sure if you ask him nicely he'll let you look once in a while.
Seriously, they are an expensive item to be toting along. It's your call, of course.
Pick your taxidermist ahead of leaving on the trip. Join SCI and get their magazine. (beautiful glossy covers) It will have ads by taxidermists. You want a taxidermist who knows what a live duiker looks like and can make the eyes look alive. It's what will determine the whole look of your trophy so make sure you have this guy lined up. (He can also supply shipping tags and labels so that when your trophies come into the States your Customs agent will already have them - I recommend somebody like Fauna & Flora in NY to handle the formalities of getting your trophies through Customs.
Oh, yeah , final advice - Enjoy the trip!