Hunted Damaraland in Namibia last October, awesome doesn't even start to describe it. We hunted 1.3 million acres of unfenced concession, photographs don't do the scenery justice, and the hunting was phenomenal. Can't recommend it enough, have also hunted south Africa but enjoyed Namibia more as it was unfenced.
As for calibres you can't go wrong with one of the .30 calibres, four us went one mate had a 30.06, other two mates had .308 and i had a .308 and .375 H&H,( two barrels for my Blaser) i shot Mountain Zebra, Kudu, Gemsbok, and baboon, he was in the wrong place at the wrong time, the .375 barrel was on and we bumped into a troop,with the .375 and Springbok, Jackal and Steenbok with the .308.
The .308 was a bit over kill for the steenbok, but for the gemsbok, it was taking roughly on average about three shots to put them down, and this wasn't bad shooting my mate put three bullets in a triangle at distances varying from 150m-250m on the shoulder of one bull and eventually the fourth shot broke a front leg and it went down, incredibly tough animals. The first shot would have killed it but they can go a long distance, my mate was beginning to think it was bullet proof.
On this trip i did fall in love with my .375, my gemsbok went down after about three or four paces, shot at 210m and the zebra went about 40m in a circle before going down and the kudu was alot closer but did go down, but was thrashing about on rock so i shot it again in case it burst a horn.
The .308 and .30.06 accounted for everything if not as effectively as the .375, two of my mates were culling and shot about 25 animals between them, so they .30 calbres did do a job, but i would be a bit wary of anything less, they were using 180grain bullets.
Go on get it booked, you won't regret it.
Moose