The tool jacobolus is referring to is a color scheme editor I made: https://www.colorize.io/baskerville/RVXGW50G/ https://www.colorize.io/baskerville/RVXGW50G/.

The tool jacobolus is referring to is a color scheme editor I made: https://www.colorize.io/baskerville/RVXGW50G/ https://www.colorize.io/baskerville/RVXGW50G/. It was, indeed, originally based on HuSL, but I later realized I could get a more meaningful picker by just constraining the chroma component not to go beyond the maximum in-gamut chroma for the given lightness and hue.