I have done what you are asking twice.
Here are some tips and observations;
As much as it sounds great it's ALOT of hunting to go more than 10 days with out a break.I break my hunts up into segments based on areas and desired game from that area.Just like you find good whitetails in specific states,African animals are the same,research what you want,and where to find good ones.For example,Nyala in Kwa-Zulu Natal are better and cheaper,but Impala are smaller there in general,better to go for in Limpopo areas for Impala.
See more of Africa than the back of a pick up and a hunting camp.Lots of cool stuff to see,an nice people to meet.Can't stress this enough,many hunters I have talked to often just see airplane,camp,airplane;and don't get to really meet different cultures.
I use a different outfitter for each segment.As much as I have enjoyed each PH,after 8-10 days,I'm done.I'd much rather meet several,then decide who I would return with.In the 2 long hunts I used 5,2 the first trip,3 the second.I have gone back to one,and will use another for part of the next trip.I had one that I couldn't stand(lazy and wanted to just ride around),and it was great knowing that it was not forever.I did put my foot down and ended up taking some nice trophies,but having to complain to the owner of the company sucked.
I consolidate shipping and taxidermy dip and pack using one company.It's cheap to get the stuff moved around to one location.I work all this out before hand with the outfitters,so everyone knows going in.One didn't want to accomadate this,so I booked with someone else.He was suprised to meet me in the airport,with a camera loaded with pics,giving another PH a tip.LOL
Work out some cull pricing to get hunting all the time,I book later in the season,so there are always quota to use.I even negotiated right in a store for some Impala culling on a farm near by.I have taken lots of male/female combo's of the same specie.They look great mounted together.And flat skins also for pillows or rugs.
This is just my situation,you may want to spend 20 days moving around with the same crew(PH and tracker/skinners).I take a lot of time to plan everything out,it keeps costs low;which equals more hunting and site seeing time in country.I'm all about making a long trip for more value.I can take the month off of work if I plan ahead.I travel alone,so I can be pretty flexible if need be.
Last long trip in 2007(I did a short hunt in 2008)I was in Namibia and South Africa for 30 days(plus 4 flying),of which 20 were hunting.Shot 42 animals,24 that I kept,9 are trophy males,12 are either varmints or flat skins,rest are culls where the animal is the property owners/outfitters.That's one good animal for 2 days hunting, about average IMO.I did alot of site seeing,Etosha a couple days,Windhoek 2 days,Bass in Jozini Dam for a day...etc.
Good luck,Africa is awesome....
Dinsdale