Your 300 or 30/06 will be fine for anything including the eland. You need to get hold of your safari and let him know what fire arms you intend using, model and serial number, so that he can arrange a import permit for you on the South African side, just to make your trip hastle free. The documents need to be posted to you so that you have them when you land in SA. The amount of fire arms that you are allowed to take with is up to you, the question is how many fire arms will your airline allow you to carry? This also needs to be pre arranged well ahead of time. I belive there are a few airlines that have stopped carring fire arms.
If I take a gun, must that gun return with me?
If your fire arms are all on one export / Import permit, you will have to explain why you left any fire arms behind when you return, these situations can get a bit ugly. If you have someone traveling with you that is a non hunter, get them to export the fire arm out on a seperate permit. If you intend donating any fire arm to your guide, he will need to keep your permit so that he could register the fire arm on his name in SA.
Africa is a great place to hunt, you will enjoy every moment of it. Good luck.
http://www.mabelingwane.com/
Aim to please.