mumbles something about horse shit then staggers outside and simultaneously pukes, shits, pisses, shoots two snot balls out his nose and ejects enough wax out of his ears to start a candle shop and never spilled his beer.
Perhaps that is part of the problem.
Let's face some irrefutable facts here.
The faster the bullet goes, the further it will go, the harder it will hit. There is simply no discussion on this. There is no wiggle room.
True.
However, when comparing the 30-06 vs 300 Win Mag, as this is the OP's question, there is a lot of discussion and a lot of wiggle room.
He is very comfortable with his 30-06 not so with the 300 WM(as he states).
Does he need the extra velocity and recoil and does he need to worry about that when he needs to take a prone shot over a rock at a possible up or down hill shot with the 300 WM if he is not comfortable with it?
Most certainly not, he will be better off with the 30-06, he will aim better, and shoot better because he is not concerned with the recoil.
If he is aiming with that same aiming position, the thought will go through his mind how is the 300 WM going to recoil and just there the shot placement could go south.
For the OP he has answered his own question and the obvious choice for his needs would be the 30-06.
As for snot noses using 30-378 Weatherby's or a user of a 30-30 mumbling horse shit then staggers outside and simultaneously pukes, shits, pisses, shoots two snot balls out his nose and ejects enough wax out of his ears to start a candle shop and never spilled his beer, it is irrelevant to the OP's question and I ques they can use whatever floats their boat.
MOST hunters are better off with rifles and cartridges they shoot well, that should be the main criteria when deciding what rifle to take to Africa for PG, not the one you are not comfortable with! Assuming of course it is in a legal caliber which both the 30-06 and 300 WM are.
Take the gun you are comfortable with and shoot well and with premium grade bullets you will be fine.