C ROY,
Since you mention black wildebeest, I assume you're hunting in South Africa. If all the hunting is going to be on a ranch, then there won't be much trouble locating buffalo. In that case, it might not be a bad idea to warm up on a couple head of plains game.
When hunting buffalo in "wild" Africa, on the other hand, it makes more sense to go after them first because they're not so predictable, and see what happens with plains game along the way.
