i mean i use the L bow and other PVC pipes to construct the overflow.
and the pipe will run across the tank (under the DSB ) to the left of the tank, then join with a vertical pipe as the overflow.
please refer to the picture..
the black area refer to the L bow and the pink area represent pipes under the DSB and the blue dot refer to the vertical pipe that is link from the pipes (pink) to the surface of the water as overflow.
....
sorry for my bad phrasing..
any disadvantage for this setup