Can you elaborate? Why wouldn't it work?
Another option is to make your own clipping indicator, for which there's plenty of tutorials on the web. You just need some basic electronics knowledge. Then set your gain backed off of clipping on the loudest volume you'll play your system at. From there, watch the indicator and make judgements if you need to tune the gain further.
To be clear though, I'm not knocking the DD1. If you have the money, go for it because it will simplify the process and is cheaper than a scope. Steve's videos point out that although a scope shows you everything about the signal, you need to know what distortion actually looks like. The DD1 has a simple light that blinks and tells you to back off. Now, is it too sensitive and can a quality system handle some soft clipping and minor distortion in exchange for more output? That's a judgement call.