I have given up on that site a long time ago as it stopped working for me. FWIW, I saved this PDF version back in the day when I found it useful. The downside is that the pages are saved in a print mode that creates multiple pages for a group of line items so it's a bit hard to follow.
I've since come to rely on mix suggestions from various sources and on my own experience to come up with the colours I like. I've made, and continue to update my own notes for this.