I'm not sure if this is the answer you are looking for or not. In preparation for my safari in 2022, and this Jun, this is my training routine. I set two targets, one at 50 yds, and another one at 100 yds. In 2022, I used a 22, and a 375 H&H that I was taking. This was routine. I'd fire the 22 at the 50 yds target which where smaller, I'd then switch to the 375 H&H fire 3 rounds at the 100 yds target. I'd then switch to the 22, and then 375 for at least 2-4 different sessions. I always ended the sessions with the 22. I did some shooting at 200 yds with the 375 to see where it impacted, but most of the shooting was done at 100 yds.
For this year's safari, I'm shooting a 22, a 300 H&H and a 416 Rigby, I'm taking the 300 and the 416 to Africa this time. I basically do the same as above, but now, I have 3 different calibers I switch to. Oh, and all the shooting was/is done from shooting sticks. Nothing from the bench.