Safari?

I am an amateur photographer (likely an advanced amateur) who is going to do the "once in a lifetime trip" to Africa. I have been shooting for 30 years and have ok equipment (know that I will need a 500mm and teleconverters ) BUT I am lost as to how to choose a "safari". I am interested primarily in large animals and secondarily in birds and landscape.

I will travel with a companion who is also a photographer. Any suggestions?
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AMFND