It is apparent that one must draw a line between the PH's rifle and the clients. The client's rifle will be called upon to take a variety of game weighing as little as a dik-dik or as great as an elephant. The range he shoots at might be from a few feet to several hundred yards. The .375 gives a client a single rifle solution to all these possible scenarios.

The PH's rifle on the other hand is for when things go wrong, and as you have pointed out, sometimes things go horribly wrong. The PH's greatest weapon is his brain, and when his brain fails him, his choice of rifle is of little consequence. All PH's are human, and as with any such diverse group, there will be a great range of shooting ability and tolerance to recoil amongst them. I would therefore sooner hire a PH who was smart and competent with his rifle, rather than hire a PH based on his rifle's bore size.