Re: Guys....
Well, there are not too many high parts in that song - other than the ad libs... (Btw, I think Bobby is awful in that video...)
Furthermore here's a link to the song's background on wikipedia. It clearly states who sings lead and who sings backup. If you don't believe that, you might want to check out your Toto IV album cover, too
http://en.wikipedia.org/wiki/Africa_%28Toto_song%29