I've hunted them in Zambia and Cmaeroon. I wouldn't go to that area of Cameroon today, to stick to Zambia. I hunt with Johnny DuPlooy but Alister Norton is top also and if I'm not mistaken is DuPlooy's brother in law??? Not that many Alister's outfitting in Zambia, right?
Be aware taht roan are not necessarily plentiful anywhere. You get them when you get them. Never a guarantee unless you ranch hunt.