Have they not given you any guidance on this? I would go with the 300wm personally its a nice round and will give a clean kill on what is a large animal anyway. I have a budyy thats been there several times as his wife
( deceased) came from there originally. He has told me all about his trips and one thing I do remember is you have to qualify before they let you shoot live game. I seem to remember 100yds off hand 4" circle 300yds off rest and 75 or 100yds at running target must be in the main heart lung area. I will be talking to him this week sometime on the phone and will ask him again as I am not sure of the detail. I will pm you with info. He used my 300wm on the last trip, previous ones he used a 8x68 jrs which is a european cal. He got two with mine so I was pleased for him with that.
Better the man suspected of being a fool keep his mouth shut, than to open it and remove all doubt.