I can tell you PHs (and Guides) HATE muzzle brakes for obvious reasons.
+1 on that. Anyone who has hunted much with someone that has a muzzle brake will hate them due to the noise and the resulting damage to eardrums.
The M70 in .416 Rem, even though it is heavier than it needs to be, is still lighter than the Ruger RSM Rigby. I'm sure the PH's rifle with the Hogue stock is even lighter. Makes sense when you have to carry that rifle every day. I also bet he carries the push feed because that is what he could get his hands on, not necessarily what he would choose if he had a choice.
As for solids, I agree that they make sense for the PH, not necessarily for the client, though. I will say that when I was tracking a wounded buff bull that had a messed up leg due to poacher's snares, the PH didn't want him getting into the long grass and wanted to make sure we cut him down right away. At that point, he instructed me to switch to solids, which I did. A quick lung shot stopped him and put him down, so the solid worked just as well as a soft in that situation.
