I want to expand my answer. I would recommend only taking the mauser in 9.3 x 62. Laws, regs, luggage etc are major factors in this decision. The weight shotgun ammo is the killer. You are allowed 11 pounds of ammunition and many times they weigh the case, locks and all. This limits you to 50 rounds of 9.3 x 62 or thereabout. The ammunition you bring in must be for the gun you bring in.
Most likely the outfitter/PH will have loaner/rental guns available and matching ammunition available for purchase. You most likely would rather have your rifle as you can brag later that I killed this animal there with this rifle right here. You can use a loaner shotgun to do all the wingshooting your heart desires.
Another big reason I would only take one is luggage. If I were to go again I would take one rifle, my 375 H&H and have it in a soft case inside the hard case. My rifle banged me, the roof, the windows etc getting from point A to point B. I held it as tight as I could, but couldn't control it and this was not from a crazy driver driving wild; this was from the ruts, holes, hairpin turns etc. It would have been a breeze if it was in a soft case.
The weight projectile is your choice but I would pick the flattest shooting heavier round, not the heaviest available round. I would use Nosler Partitions for Impala and up; Solids for Springbok and smaller, or Partitions for it all.
I would use a pre approved rifle permit. I used rifle permits.com. I would not do anything special. I did not make up those caliber regulations. I was told those very specific examples across the board by everyone, i.e the outfitter, in person, face to face in Harrisburg at the Great Outdoor Show, the packet from the outfitter, Henry from riflepermits via email. What may slip by one day may not slip by the next. Don't rely on incompetence and bribes.
I will relate that my son and I did this trip by ourselves. We could have used a night in Jo-berg. It was tight making the connection to Port Elizabeth. I was lucky that I went with the pre-approved rifle permit. The schedule was so tight due to a huge plane from Australia landing ahead of us. The line at Customs was 3 hours!! The guy at the ticket counter just grabbed the bags from my son and in the flurry my son didn't have time to tell the guy that he needed to pull the ammunition case out of my bag. When we claimed baggage in Port Elizabeth there was big strips of yellow tape in X's all over my bag and words that I didn't understand. The PH said that it was my ammunition in there being detacted and that they probably took it. They didn't for whatever reason; it was packed/locked properly and they either let me slide or got side tracked and let it proceed that way, but I wouldn't count on the same result next time.
Now not confuse this with the whole Temporary Import Permit regs etc, but when talking with my PH one evening, he was telling me about the gun laws in RSA pertaining to their citizens. He told me the citizens were allowed 2 rifles, a shotgun, and a handgun. I don't recall if they had to be different calibers like the Temp Import Permit or not, but another interesting point he made was that the citizens could only have one rifle with a 2 as the first digit in the caliber, i.e. either a 270 or a 22 Hornet, not both. The second rifle had to be larger than a 2. The PH also informed me that PH's were authorized to own quite a few firearms as it was for their job.
One other consideration is the whole bribes and payoffs. A $10.00 bill will work wonders to correct an oversight/error. There are also the ever present shakedowns and scammers in uniform and out. You have to pay attention. The pre approved process negates much of this.
