@Lumaberpat, you have come to the right place. AH is one of the most valuable resources on the web. Many fine gentlemen, and ladies that share their vast experiences and opinions. Several are excellent enablers to help you spend your money on rifles, scopes, etc.
Let me see if I can help you spend some money.
Firstly, I am still in the planning stages for my first African safari, which will include PG and buffalo. I have been accumulating rifles for over 40 years. I have a few opinions on choices, as well as reading everything I can here, and other sources to hopefully make a few informed choices. The veteran Africa hunters here will be able to give you valuable real-world experience.
Regarding rifle choices, are you willing to take up reloading?
This can make a big difference in choices. I took up reloading over 20 years ago, when I bought my first (of many) .375 H&H. Cost savings was an important factor, as well I always wanted to, and reloading will help you become more familiar and confident as a rifleman. I reload for .30-06, 7x57, .35 Whelen, and currently .458 Win Mag.
If you will reload, I would get a Winchester Model 70, 375 H&H and learn to load with lighter (250/260 grains) bullets, at moderate velocities (2500-2600 fps) and use it for all stateside hunting. No bloodshot meat at these velocities, less tracking, and moderate recoil. A .300 WIn Mag, at close range with a 165 grain bullet definitely makes more of a mess. When the country boys in camp ask
"What you gonna shoot with that thing?" the simple answer is:
"Pretty much anything I want." You won't be overgunned and being very familiar with that one rifle builds confidence.
Shouldering, scope alignment, sight picture, trigger, bolt throw length all become second nature. You create that muscle memory that is important in a tight spot, or the moment shooting that buffalo.
If reloading is not an option, then I would get a M70 in 30-06. Bolt throw is only slightly shorter than the eventual .375 H&H compared to a .308 which is definitely shorter. I have gone from a .308 to .375, and depending on the rifle, have short stroked the H&H. Build that muscle memory with the "standard length action, not the shorter .308.
With modern bullets, available in factory loads, the 30-06 will do all that is needed to hunt in the States, with the exception of big bears. Ammo is available worldwide. Lots of choices for bullet weight and types. Barnes TSX, Swift A-Frames, and others just work. Hell, Remington 180 grain CoreLokt round nose are still popular here for the thick woods,
Then step up to the .375 as you prepare for the buff hunt. Same platform and maker so the manual of arms is the same.
And spend good money on scopes. At least as much as you spend on your rifles. Buy once, cry once is very true in choice of optics. A cheap scope will eventually cause some problem, whether holding zero, consistent optical resolution, and then the cost of wasted ammo when you can't sight in.
Leupold, Swarovski, Trijicon are favored here by many. As my eyes really suck, I find it's a personal choice of what I can aim better with, depending on model, power range etc.
And get some shooting sticks and practice, practice with these.
Let us know how we can help you spend some more money!