Bow deeply and show respect where it is deserved. But don't spend too much time thinking about proper procedure at the expense of actually showing proper etiquette. Do what you feel is right. If you mean to show respect and good etiquette, but end up saying the wrong word by accident, this will not really matter all that much. Your true intentions usually show through.
People usually see others for who they really are.
For more on dojo etiquette, please see the Yale dojo site.