To catch breaking bass, you must hit the area while they are up. Baits that work for sub-surface, as well as deeper schooling fish, include a whole range of diving crankbaits and the standbys, lipless cranks. It is interesting to note that I don't see many people relying on spinnerbaits as part of their school bass arsenal. These really are great baits for catching schooling bass, though, and should be used with sub-surface or countdown retrieves. Learn how long it takes for your favorite spinnerbaits to fall and plan you retrieve rate to permit working a given strata of schooling areas.
Depth is important because larger fish in schools are often below the more active fish.
We tend to think this is because they are older, wiser, and picking up wounded prey that the masses above them knock down. Another given is that larger bass track schools of smaller bass and feed on their unsuspecting members who are concentrating on shad. This larger, bass-colored bait should also be tried, particularly if the schools appear to be made up of smaller fish. If the bass go down and hold in fishable areas before surfacing again, you are in luck. These locations are where you'll need to work a soft plastic bait or spoon or tail spinner such as a Little George.