That's exactly the approach I started using, after reading that article a couple of months ago, and it's made everything so much easier. There's no more constant tweaking of colours once I have the main palette set, and colours are much more consistent. Before this, I never realised how many colours I actually need.

Following the advice in the article, my current project has six hues, each of which has 9 shades. I really like that diagram of the chat UI that shows all the different colours that were needed.