The critical thing with a cartridge bearing is ensuring that what is used to retain it in place on the axle bears on the inner race (the part that sleeves on to the axle), and that the pressure is pretty light. Otherwise, pushing too hard against the inner race will push the bearings to one side on both the inner and outer races, increasing wear and likely causing a degree of binding.

The American Classic data sheet says to adjust the freeplay with the lock nuts such that there is a tiny bit of "wiggle" on the rim of the wheel. If that wiggle isn't there, the lock nut has been tightened too much. If the locknut too loose, you won't interfere with the free run of the bearing, but the inner race may work its way loose, and cause the outer race to wear away the hub.

Using a lock nut or retain on the outer race of a cartridge bearing is pointless as that won't stop the inner race from moving on the axle. And anything that bears on the seals is asking for disaster.

At least, that is my take on it.