Most of the time in Southern Africa you would not need to worry about flying in Cloud's.
In a light aircraft however good an instrument pilot you are you would not want to fly in or near African thunderstorms. I came out of Dalaman in Turkey last week and we went through the edge of a storm (fault with the weather radar range function) and the ride was quite rough in our big shiney jet. Storms in Turkey in May are just babies compared to the monsters you get in Southern Africa!
With reference of the thumb method above. Take a half full bottle of water. Hold it in front of you so you are looking across the top of the water.. Cloud below the top of the water then over the cloud you go. Cloud above the top of the water then into the cloud you go.