Welcome

I second Mac's comments. Start off with the best round, the .375 H&H Mag and build up from there later if you wish.

Adding a later double eg a .470 to a .375 is just so wise.

Don't go for one of those Ultra's, or whatever they are called. You will only have to load them down to get adequate bullet performance anyway.

Whatever you do, have fun.

PS Lots of people still use a .458 Win Mag and it still works for them.