OTW.... guys who posted before you say that you don't need a backhand overhead, I'm responding to them.
Dominic.... you don't always need to apply serious power to every equation. A sharp angle forcing the opponent to run well wide of his doubles alley and short of his service line can set yourself up for the next open court winner. Once he thinks you're going short angle wide, you poke one deep DTL for a clean winner, wrongfooting him.
Most overheads that you expect to be a forcing shot or winner is hit from within 3' of the service line. If you're hitting backhand overheads at your own baseline, it's probably not going to be a winner/forcing shot.
From the service line, you have lots of CC short angles to play with. You practice hitting a BALANCED 1hbh backhand overhead, that goes short of the service line, and wide enough to run the opponent past his doubles alley.