John's about right (as usual) in what he says. There's really 3 tiers in the tipping system. The lowest being the tent attendants and laundry staff etc, then comes the waiter and chef etc and highest comes the hunting staff which should include the skinners who work hardest of all yet sometimes go unappreciated.

As to PHs, well that varies enormously. I've never been given a rifle, double or otherwise, but I live in hope!

How you tip is often more important than how much you tip. In Tanzania for example the client (and party?) should sit with the PH and call each member forward one at a time and spend a few moments telling each member of staff how important their role was in making the safari such a success and a pleasure. If you just give them the money and call the next one forward (for example) they feel unappreciated. Hunting staff especially value the bond that builds up between them and the client(s) and those few words of thanks go a long way to let them know their efforts were appreciated. After all we're all part of a team out in the bush, and we all have to work as a team to get maximum performance for the client.

I personally find that this approach ensures that whenever I return to a hunting camp my return is greeted with genuine warmth rather than being greeted as just another punter.