Please help! I have a customer wanting two cakes, white and carrot, for a renuion and she wants round cakes. She needs to feed about 50 total, but she wants to slice the cake like a pie! What size would you recomond doing? Please help!

I do 3 layer-9" round cakes and can get 14 slices out of them, so I would suggest doing 4 of that size in order to safely feed 50 people. You could always go bigger but that is the minimum I would do!