I would have used the Sovereigns, due to their speed and power, for hit and run missions. There were also so few of them, they could have also be clustered together to draw the Dominions attention away and open up a station or planet for attack by other forces.
Intrepids were fast and powerful too. They may also have done hit and runs with the Sovereigns or been used as quick responders and border patrol.
The Galaxy class ships would most likely be fleet command ships, front line with a few of their fleets defending key worlds. Planets furthest away from fighting would be relatively unprotected.
Akiras, and the other new or newish ships would be front line combat ships accompanied by the Excelesiors and Miranda class ships.