This too is one of my favourite questions/quandries/situations. I may ramble on a bit here.

I don't think there is an answer. As you are from Gauteng, this will be heavily loaded towards Africa. Ultimately the choice of chambering (calibre) and shot placement must be capable of making a clean kill without the game suffering. As we know, this does not always happen and would probably include the .22lr for just about any animal.

I firmly believe a lot of people go to Africa overgunned.eg taking a .375H&H for PG
I think a lot of shooters don't know when NOT to take a shot.
I think a lot of trophy hunters rely on canons to get their 'prize'.

I select or purchase a rifle in a particular chambering more often than not to suit the terrain and hunting conditions rather than the animal hunted.

Example 1: I have a .218Bee for hunting in very steep and heavily timbered country. Why ? It is quiet and will not disturb game. I use W-W 46Hp's despite some feral game reaching 80kg liveweight.
I would use the same rifle with Norma 50 FMJ's to cull any PG with head shots under a spotlight. Unethical ? definantly in the US.

Example 2: I have purchased a .264WM for a future Springbok hunt loaded with 129 Accubonds. Adequate ? Yes. Why ? From experience it has the range on the Grassveldt (and in the Karoo) and shoots cloverleafs with that projectile.

Example 3: My custom 7x57 which shoots 175 grain projectiles the most accurately. Overgunned for local game ? Yes. Adequate for PG ? Yes. Capable of taking any soft skinned animal on the planet ? I would use it because it is my go-to-rifle and I know it perfectly. With the right 175 it will penetrate just about anything. Many would say there are better choices. For walk and stalk, it gives me the option of any shot angle I choose to take here in Oz.

Example 4: My 9.3x62. Built for Eland in the Limpopo. Capable of the largest non DG PG ? Yes. Overkill ? I think so. My old .308W with 165 Woodleighs would have done the same job. I had the 7x57 built to replace the 9.3 in Africa. Capable of culling introduced pests up to 600 kg + with less than optimum shot placement ? Devastating.

Would I use a .22 Hornet or my .218Bee on Deer or Impala sized game ? Yes if the bush was thick and I had a lot of time to take head shots.
Would I use a .243W for Kudu ? Yes, with a tough projectile like the 100 grain Premium Remington Core-Lokt.

Edit: I just read NitroX's last post. Would I use a .243W on Eland ? Probably not. It is an animal I have experience of only one, with. Would I use a 6.5mm or my 7mm with heavy for calibre projectiles ? Oh yeah.