A bush flying course is useless to be honest. Sure it's a fun way to get some hours but the flying it teaches in impractical in Botswana.
A C210 rating isn't that good for Botswana. Sure there is a few companies that fly them but not as the mainstay of the fleet.
A 210 will help you in getting a job in Namibia however.
A C207 will only get you into one company in maun.
C206s are handy, but companies are slowly phasing them out. You will need on to be considered at wilderness however.
A GA8 rating is worth it's weight in gold. But only in Maun...