3607 Electric Head

I have a 1989 3607 with manual heads. I am contemplating installing an electric head with built in macerator in the aft head. The boat was obviously wired for electric heads when built, as there is wiring and switches mounted in both heads but no breakers were ever installed in the panel. Does anyone out there have a similar setup and what head do you have? The main reason for switch is just to get a normal household size toilet for comfort, cost is a factor. I am thinking another manual head will do but since all the wiring is there electric might be the way to go.