Hmm,
i have to confess, that i don't really know what regular overflows in the US are ;-).
But i would recomment to use an overflow, were the water ist not "falling" down a shaft and hitting ground or other water down there. This would of course produce sound, which is doubled with waveboxes.
Personally i use an overflow, where the waterlevel is near the waterlevel of the tank.
That's an overflowbox with two drillings.
The pipes connected to both drillings are led into the sump.
One of them, which ends at bottom of the overflow-box is the main-overflow-pipe and has a valve, outside the tank. This valve is to be closed slightly, so the waterlevel in the shaft rises slowly. Depending on how far you close it, you can adjust the waterlevel in the shaft.
It's adjusted for the waterlevel to be 1" less than tankwaterlevel.
The other pipe at the other drilling continues inside the overflow and ends 1/2" below or at waterlevel of tank, its for safety only, if other pipe gets blocked. (As its damed up, this could happen). There is only very little sound.
best,
Ralf