Bruce Griffin courteously provided the link to the MRH color matching guide:

The link to the MRH Guide is https://www.testors.com/~/media/DigitalEncyclopedia/Documents/Testors/ebook/MRH-Acrylic-painting-guide-post-Floquil-Portrait.ashx

Considering that Testors/Rustoleum recently announced more discontinuances of their model-focused paints (no comment!) I wonder how long this document will remain on their domain.  A download of this guide should be easy.  I'd recommend it.

Cheers,
George Irwin