I also am (was) both American and British (now only British), can't afford to remain American, the only country in the world that makes you pay income tax even when you don't live there.
I am married to a Kenyan, and stayed in a tent in Namibia and Botswana for about 6 months. (that sounds like a small amount of African experience, but actually I've significant time in Africa, I just want to point out that I am familiar with Botswana, Namibia, and East Africa)
Having 2 passports has an advantage in that you can enter the country on one passport, get a 3 months visa, leave, and re-enter with your other passport for another 3 months. so you can stay 6 months in one country each year "legally".
having that many hours isn't necessarily a benefit in places like Botswana, as they normally want 200 hour newbies, although they have hired people with more hours, its just not the "normal" way of working - and for that I would email the chief pilots and tell them you're coming, and that you have 2000 hours and the real reason you're going to Africa is not to get hours to go on to be a jet jock, but you want the experience, etc. blah blah blah.
However, if you didn't like Nairobi, you ain't going to like much of living in Africa mate. Nairobi is one of the better cities outside of South Africa. (although SA has some not so good cities too)
Botswana and Namibia have been called Africa for beginners, and for good reason. And when you go on a safari, or climb a mountain in east Africa, you aren't in Africa, you're on a tourist reservation. Kind of like going to a casino in the US and saying that you've spent time with the natives on the reservation.