If I went to Africa I would want to hunt a Cape buffalo, I’d it normal to go on a first African hunt and not shoot plains game? Or is the plains game the get used to travel and how it all works before stepping up to the big stuff?
There was a well known talk over a campfire on the farm where I was hunting.
A German hunter came to Africa to hunt buffalo.
So, they asked him what did he hunt before?
He said, nothing in Africa, this is my first time here!
My friend told him, sorry but did you start reading hunting book from backwards, never hunted in Africa and go for buffalo first? (as a joke)
He did collect his buffalo later.
I heard a story when a European hunter came on farm, with request to hunt "everything available around".
He did it in 2 or three weeks. And will probably never return to Africa.
Next hunt he will go maybe to New Zealand, or to Australia, or Kamchatka, or somewhere else. He just hunts everywhere, and with this hunt he made a check of Africa on his global check list and moved on.
Is one hunt in Africa enough for individual hunter? For some, yes. For some not. Nothing wrong either answer.
How do you feel? Hunting buffalo, and never see Afirca again, or maybe to repeat? Every answer is good one.
I went to safari three times for plains game, before getting to buffalo on my 4th safari, few weeks ago. It seamed that each hunt I made, was more demanding then previous one. (my third safari for eland, was not easy - I made report here, Check title, "Namibia: from the smallest to the greatest" ). And my hunt for buffalo was much more then that.
So, my 4th safari was for buffalo. (Report pending to do, will be soon posted here)
By the time I got to buffalo level, I already had a taste of Africa, read many books about African hunting, history, and about buffalo. I heard the stories over a camp fire about buffalo, about dangerous game, bullets, rifles, failures, trophies and disappointments when the game was lost.
I think that entire preparation for buffalo, and earlier plains game hunts, interaction with trackers and PH in the field, shooting from stick, etc... can be seen as a "foreplay" adding to full dangerous game hunting experience. It made it better!
Plains game hunting as a overall preparation for this.
Does the alpinist go to Himalaya first, or he starts by climbing his local hill first?
Some people go first for dangerous game, then whatever else they had in mind.
it is all about experience they want to get. Is hunter just a trigger man, or expects more from the experience, to be more psychologically and emotionally involved?
The motivation can be intrinsic or extrinsic. Some go for experience and interaction with people and connection with animals, for this: preparation and experience is needed, and for extrinsic -some go ad-hoc shopping for horn.
I cannot say which is more valid motivation.
But I can say, the more you learn before, the more experience you get before, better will be overall experience after you evolve to get to dangerous game hunt.
My way to buffalo was hunting on a farm, first plains game, in open range and high fence. three times.
Then when I got the idea to hunt buffalo - the idea was born in Africa, then I bought the 375 rifle, then when I started planning - next consideration was shall I hunt buffalo in high fence (South Africa, nothing wrong in that, and much cheaper) or wilderness area (harder hunt, and maybe less chance to success, and more $$$).
So, I decided to go wilderness area for my first buffalo hunt.
Anyway, this was my way and my thinking but it does not mean that your decision will be wrong, and whatever you decide is OK.
Certainly your idea to buy DG rifle, and get it prepared in time, is valid one, it will add to entire experience later. For the rest... keep planning.... and valuating... till the time comes...
The 30-06 performance is very close to a magnum with less recoil and especially without that hard snappy recoil of a 300 Win Mag. And bullet trajectories for most factory 30-06 180 grain loads compared to a 375 with 270 grain loads are nearly identical. With the 375 H&H 300 grain loading being very close. 
Please think twice about a laminated or composit stock.... think of the rifles having Soul after you hunt with them in Africa. 
