It seems you are conflating two different topics here, one of splitting future titles and working order and the other of presenting things externally.
Figure out now how you intend to split the roles between you and how you intend to work together. The CEO will be in charge of the CTO.
After you figure that out figure out how you are going to present things externally and on business cards. For a two person company co-founders seems better but it really depends on you two and your views.
Comments
It seems you are conflating two different topics here, one of splitting future titles and working order and the other of presenting things externally.
Figure out now how you intend to split the roles between you and how you intend to work together. The CEO will be in charge of the CTO.
After you figure that out figure out how you are going to present things externally and on business cards. For a two person company co-founders seems better but it really depends on you two and your views.