If I wanted to create a large 5ft by 6ft colour mural of people, I'm guessing the best way to do this to shoot a low ISO film - like Kodachrome 64 or Fuiji Velvia 50? Transparency over negative - which is better?

I don't have access to a 4x5 so an internegative would have to be made from my 6x6 to blow up from, right?

Help....