RIPP's citation is interesting.

I like this Robertson fellow.

His recommendations often check out with my testing. For example, this bit. In my media, I have found mere bullet WEIGHT to be a very poor predictor of bullet penetration AND recovered expansion weight and diameter.

Sometimes a light bullet will penetrate more deeply and expand better than a heavier bullet. Sometimes not. Bullet construction is the key.

As NITRO and RIPP intimate here, check with your PH. If he has any time in the field at all, he has opinions, and since you are hunting with him, take his advice. If he doesn't know what to pick...don't hunt with him!

Having said all that, as RIPP said earlier, a well-placed 165 grain bullet from any of the major manufacturers is going to kill a kudu.

One last thing. It makes lots of sense to practice field position shooting before the hunt. Doing so with Premium bullet can be cost preventive. So the use of a similar/same weight cheaper bullet for practice makes good sense. However, do not assume the same weight bullets will print to same POI. Make sure you shoot enough of your hunting bullets to know where they will print at all reasonable ranges.