The original question is about a guide, that's a PH not a tourist hunter.
The main roll of any PH is to make the client happy and keep him safe (just to make him come back again

). That's why I think a PH should use a double with both solids bullets (I mean hunting elephants) . He's not hunting, just protecting the client if necessary. A couple of 500 grains solid bullets will do the work.
May be one of each kind while hunting buffalos or Hippos is Ok, but I don't like while elephant hunting

I'm so sorry but I think that way. I'll never mess with any PH who carry a bolt action rifle (almost them), may be my bad english made a mistake but I never said a PH without a double was a bad pro or "Inexperianced" hunter.