If by "if you want to try" you mean create the scenario myself, I'm afraid, not this year
I have absolutely zero experience in meddling with it
As for fight the AI with stones and arrows, that's the idea, isn't it?
Or, use some thinking, the AI should be slow enough in colonizing for the African Nations to let the colonizers at peace for a while, until they themselves gain some strength and knowledge.
Maybe rework some tech stealing mechanics?